diff --git a/vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go b/vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go
deleted file mode 100644
index 297492e..0000000
--- a/vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go
+++ /dev/null
@@ -1,457 +0,0 @@
-/*
- *
- * Copyright 2018 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-// Package dns implements a dns resolver to be installed as the default resolver
-// in grpc.
-package dns
-
-import (
-	"context"
-	"encoding/json"
-	"errors"
-	"fmt"
-	"net"
-	"os"
-	"strconv"
-	"strings"
-	"sync"
-	"time"
-
-	"google.golang.org/grpc/grpclog"
-	"google.golang.org/grpc/internal/backoff"
-	"google.golang.org/grpc/internal/grpcrand"
-	"google.golang.org/grpc/resolver"
-)
-
-func init() {
-	resolver.Register(NewBuilder())
-}
-
-const (
-	defaultPort       = "443"
-	defaultFreq       = time.Minute * 30
-	defaultDNSSvrPort = "53"
-	golang            = "GO"
-	// txtPrefix is the prefix string to be prepended to the host name for txt record lookup.
-	txtPrefix = "_grpc_config."
-	// In DNS, service config is encoded in a TXT record via the mechanism
-	// described in RFC-1464 using the attribute name grpc_config.
-	txtAttribute = "grpc_config="
-)
-
-var (
-	errMissingAddr = errors.New("dns resolver: missing address")
-
-	// Addresses ending with a colon that is supposed to be the separator
-	// between host and port is not allowed.  E.g. "::" is a valid address as
-	// it is an IPv6 address (host only) and "[::]:" is invalid as it ends with
-	// a colon as the host and port separator
-	errEndsWithColon = errors.New("dns resolver: missing port after port-separator colon")
-)
-
-var (
-	defaultResolver netResolver = net.DefaultResolver
-	// To prevent excessive re-resolution, we enforce a rate limit on DNS
-	// resolution requests.
-	minDNSResRate = 30 * time.Second
-)
-
-var customAuthorityDialler = func(authority string) func(ctx context.Context, network, address string) (net.Conn, error) {
-	return func(ctx context.Context, network, address string) (net.Conn, error) {
-		var dialer net.Dialer
-		return dialer.DialContext(ctx, network, authority)
-	}
-}
-
-var customAuthorityResolver = func(authority string) (netResolver, error) {
-	host, port, err := parseTarget(authority, defaultDNSSvrPort)
-	if err != nil {
-		return nil, err
-	}
-
-	authorityWithPort := net.JoinHostPort(host, port)
-
-	return &net.Resolver{
-		PreferGo: true,
-		Dial:     customAuthorityDialler(authorityWithPort),
-	}, nil
-}
-
-// NewBuilder creates a dnsBuilder which is used to factory DNS resolvers.
-func NewBuilder() resolver.Builder {
-	return &dnsBuilder{minFreq: defaultFreq}
-}
-
-type dnsBuilder struct {
-	// minimum frequency of polling the DNS server.
-	minFreq time.Duration
-}
-
-// Build creates and starts a DNS resolver that watches the name resolution of the target.
-func (b *dnsBuilder) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOption) (resolver.Resolver, error) {
-	host, port, err := parseTarget(target.Endpoint, defaultPort)
-	if err != nil {
-		return nil, err
-	}
-
-	// IP address.
-	if net.ParseIP(host) != nil {
-		host, _ = formatIP(host)
-		addr := []resolver.Address{{Addr: host + ":" + port}}
-		i := &ipResolver{
-			cc: cc,
-			ip: addr,
-			rn: make(chan struct{}, 1),
-			q:  make(chan struct{}),
-		}
-		cc.NewAddress(addr)
-		go i.watcher()
-		return i, nil
-	}
-
-	// DNS address (non-IP).
-	ctx, cancel := context.WithCancel(context.Background())
-	d := &dnsResolver{
-		freq:                 b.minFreq,
-		backoff:              backoff.Exponential{MaxDelay: b.minFreq},
-		host:                 host,
-		port:                 port,
-		ctx:                  ctx,
-		cancel:               cancel,
-		cc:                   cc,
-		t:                    time.NewTimer(0),
-		rn:                   make(chan struct{}, 1),
-		disableServiceConfig: opts.DisableServiceConfig,
-	}
-
-	if target.Authority == "" {
-		d.resolver = defaultResolver
-	} else {
-		d.resolver, err = customAuthorityResolver(target.Authority)
-		if err != nil {
-			return nil, err
-		}
-	}
-
-	d.wg.Add(1)
-	go d.watcher()
-	return d, nil
-}
-
-// Scheme returns the naming scheme of this resolver builder, which is "dns".
-func (b *dnsBuilder) Scheme() string {
-	return "dns"
-}
-
-type netResolver interface {
-	LookupHost(ctx context.Context, host string) (addrs []string, err error)
-	LookupSRV(ctx context.Context, service, proto, name string) (cname string, addrs []*net.SRV, err error)
-	LookupTXT(ctx context.Context, name string) (txts []string, err error)
-}
-
-// ipResolver watches for the name resolution update for an IP address.
-type ipResolver struct {
-	cc resolver.ClientConn
-	ip []resolver.Address
-	// rn channel is used by ResolveNow() to force an immediate resolution of the target.
-	rn chan struct{}
-	q  chan struct{}
-}
-
-// ResolveNow resend the address it stores, no resolution is needed.
-func (i *ipResolver) ResolveNow(opt resolver.ResolveNowOption) {
-	select {
-	case i.rn <- struct{}{}:
-	default:
-	}
-}
-
-// Close closes the ipResolver.
-func (i *ipResolver) Close() {
-	close(i.q)
-}
-
-func (i *ipResolver) watcher() {
-	for {
-		select {
-		case <-i.rn:
-			i.cc.NewAddress(i.ip)
-		case <-i.q:
-			return
-		}
-	}
-}
-
-// dnsResolver watches for the name resolution update for a non-IP target.
-type dnsResolver struct {
-	freq       time.Duration
-	backoff    backoff.Exponential
-	retryCount int
-	host       string
-	port       string
-	resolver   netResolver
-	ctx        context.Context
-	cancel     context.CancelFunc
-	cc         resolver.ClientConn
-	// rn channel is used by ResolveNow() to force an immediate resolution of the target.
-	rn chan struct{}
-	t  *time.Timer
-	// wg is used to enforce Close() to return after the watcher() goroutine has finished.
-	// Otherwise, data race will be possible. [Race Example] in dns_resolver_test we
-	// replace the real lookup functions with mocked ones to facilitate testing.
-	// If Close() doesn't wait for watcher() goroutine finishes, race detector sometimes
-	// will warns lookup (READ the lookup function pointers) inside watcher() goroutine
-	// has data race with replaceNetFunc (WRITE the lookup function pointers).
-	wg                   sync.WaitGroup
-	disableServiceConfig bool
-}
-
-// ResolveNow invoke an immediate resolution of the target that this dnsResolver watches.
-func (d *dnsResolver) ResolveNow(opt resolver.ResolveNowOption) {
-	select {
-	case d.rn <- struct{}{}:
-	default:
-	}
-}
-
-// Close closes the dnsResolver.
-func (d *dnsResolver) Close() {
-	d.cancel()
-	d.wg.Wait()
-	d.t.Stop()
-}
-
-func (d *dnsResolver) watcher() {
-	defer d.wg.Done()
-	for {
-		select {
-		case <-d.ctx.Done():
-			return
-		case <-d.t.C:
-		case <-d.rn:
-			if !d.t.Stop() {
-				// Before resetting a timer, it should be stopped to prevent racing with
-				// reads on it's channel.
-				<-d.t.C
-			}
-		}
-
-		result, sc := d.lookup()
-		// Next lookup should happen within an interval defined by d.freq. It may be
-		// more often due to exponential retry on empty address list.
-		if len(result) == 0 {
-			d.retryCount++
-			d.t.Reset(d.backoff.Backoff(d.retryCount))
-		} else {
-			d.retryCount = 0
-			d.t.Reset(d.freq)
-		}
-		d.cc.NewServiceConfig(sc)
-		d.cc.NewAddress(result)
-
-		// Sleep to prevent excessive re-resolutions. Incoming resolution requests
-		// will be queued in d.rn.
-		t := time.NewTimer(minDNSResRate)
-		select {
-		case <-t.C:
-		case <-d.ctx.Done():
-			t.Stop()
-			return
-		}
-	}
-}
-
-func (d *dnsResolver) lookupSRV() []resolver.Address {
-	var newAddrs []resolver.Address
-	_, srvs, err := d.resolver.LookupSRV(d.ctx, "grpclb", "tcp", d.host)
-	if err != nil {
-		grpclog.Infof("grpc: failed dns SRV record lookup due to %v.\n", err)
-		return nil
-	}
-	for _, s := range srvs {
-		lbAddrs, err := d.resolver.LookupHost(d.ctx, s.Target)
-		if err != nil {
-			grpclog.Infof("grpc: failed load balancer address dns lookup due to %v.\n", err)
-			continue
-		}
-		for _, a := range lbAddrs {
-			a, ok := formatIP(a)
-			if !ok {
-				grpclog.Errorf("grpc: failed IP parsing due to %v.\n", err)
-				continue
-			}
-			addr := a + ":" + strconv.Itoa(int(s.Port))
-			newAddrs = append(newAddrs, resolver.Address{Addr: addr, Type: resolver.GRPCLB, ServerName: s.Target})
-		}
-	}
-	return newAddrs
-}
-
-func (d *dnsResolver) lookupTXT() string {
-	ss, err := d.resolver.LookupTXT(d.ctx, txtPrefix+d.host)
-	if err != nil {
-		grpclog.Infof("grpc: failed dns TXT record lookup due to %v.\n", err)
-		return ""
-	}
-	var res string
-	for _, s := range ss {
-		res += s
-	}
-
-	// TXT record must have "grpc_config=" attribute in order to be used as service config.
-	if !strings.HasPrefix(res, txtAttribute) {
-		grpclog.Warningf("grpc: TXT record %v missing %v attribute", res, txtAttribute)
-		return ""
-	}
-	return strings.TrimPrefix(res, txtAttribute)
-}
-
-func (d *dnsResolver) lookupHost() []resolver.Address {
-	var newAddrs []resolver.Address
-	addrs, err := d.resolver.LookupHost(d.ctx, d.host)
-	if err != nil {
-		grpclog.Warningf("grpc: failed dns A record lookup due to %v.\n", err)
-		return nil
-	}
-	for _, a := range addrs {
-		a, ok := formatIP(a)
-		if !ok {
-			grpclog.Errorf("grpc: failed IP parsing due to %v.\n", err)
-			continue
-		}
-		addr := a + ":" + d.port
-		newAddrs = append(newAddrs, resolver.Address{Addr: addr})
-	}
-	return newAddrs
-}
-
-func (d *dnsResolver) lookup() ([]resolver.Address, string) {
-	newAddrs := d.lookupSRV()
-	// Support fallback to non-balancer address.
-	newAddrs = append(newAddrs, d.lookupHost()...)
-	if d.disableServiceConfig {
-		return newAddrs, ""
-	}
-	sc := d.lookupTXT()
-	return newAddrs, canaryingSC(sc)
-}
-
-// formatIP returns ok = false if addr is not a valid textual representation of an IP address.
-// If addr is an IPv4 address, return the addr and ok = true.
-// If addr is an IPv6 address, return the addr enclosed in square brackets and ok = true.
-func formatIP(addr string) (addrIP string, ok bool) {
-	ip := net.ParseIP(addr)
-	if ip == nil {
-		return "", false
-	}
-	if ip.To4() != nil {
-		return addr, true
-	}
-	return "[" + addr + "]", true
-}
-
-// parseTarget takes the user input target string and default port, returns formatted host and port info.
-// If target doesn't specify a port, set the port to be the defaultPort.
-// If target is in IPv6 format and host-name is enclosed in square brackets, brackets
-// are stripped when setting the host.
-// examples:
-// target: "www.google.com" defaultPort: "443" returns host: "www.google.com", port: "443"
-// target: "ipv4-host:80" defaultPort: "443" returns host: "ipv4-host", port: "80"
-// target: "[ipv6-host]" defaultPort: "443" returns host: "ipv6-host", port: "443"
-// target: ":80" defaultPort: "443" returns host: "localhost", port: "80"
-func parseTarget(target, defaultPort string) (host, port string, err error) {
-	if target == "" {
-		return "", "", errMissingAddr
-	}
-	if ip := net.ParseIP(target); ip != nil {
-		// target is an IPv4 or IPv6(without brackets) address
-		return target, defaultPort, nil
-	}
-	if host, port, err = net.SplitHostPort(target); err == nil {
-		if port == "" {
-			// If the port field is empty (target ends with colon), e.g. "[::1]:", this is an error.
-			return "", "", errEndsWithColon
-		}
-		// target has port, i.e ipv4-host:port, [ipv6-host]:port, host-name:port
-		if host == "" {
-			// Keep consistent with net.Dial(): If the host is empty, as in ":80", the local system is assumed.
-			host = "localhost"
-		}
-		return host, port, nil
-	}
-	if host, port, err = net.SplitHostPort(target + ":" + defaultPort); err == nil {
-		// target doesn't have port
-		return host, port, nil
-	}
-	return "", "", fmt.Errorf("invalid target address %v, error info: %v", target, err)
-}
-
-type rawChoice struct {
-	ClientLanguage *[]string        `json:"clientLanguage,omitempty"`
-	Percentage     *int             `json:"percentage,omitempty"`
-	ClientHostName *[]string        `json:"clientHostName,omitempty"`
-	ServiceConfig  *json.RawMessage `json:"serviceConfig,omitempty"`
-}
-
-func containsString(a *[]string, b string) bool {
-	if a == nil {
-		return true
-	}
-	for _, c := range *a {
-		if c == b {
-			return true
-		}
-	}
-	return false
-}
-
-func chosenByPercentage(a *int) bool {
-	if a == nil {
-		return true
-	}
-	return grpcrand.Intn(100)+1 <= *a
-}
-
-func canaryingSC(js string) string {
-	if js == "" {
-		return ""
-	}
-	var rcs []rawChoice
-	err := json.Unmarshal([]byte(js), &rcs)
-	if err != nil {
-		grpclog.Warningf("grpc: failed to parse service config json string due to %v.\n", err)
-		return ""
-	}
-	cliHostname, err := os.Hostname()
-	if err != nil {
-		grpclog.Warningf("grpc: failed to get client hostname due to %v.\n", err)
-		return ""
-	}
-	var sc string
-	for _, c := range rcs {
-		if !containsString(c.ClientLanguage, golang) ||
-			!chosenByPercentage(c.Percentage) ||
-			!containsString(c.ClientHostName, cliHostname) ||
-			c.ServiceConfig == nil {
-			continue
-		}
-		sc = string(*c.ServiceConfig)
-		break
-	}
-	return sc
-}
diff --git a/vendor/google.golang.org/grpc/resolver/passthrough/passthrough.go b/vendor/google.golang.org/grpc/resolver/passthrough/passthrough.go
deleted file mode 100644
index 893d5d1..0000000
--- a/vendor/google.golang.org/grpc/resolver/passthrough/passthrough.go
+++ /dev/null
@@ -1,57 +0,0 @@
-/*
- *
- * Copyright 2017 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-// Package passthrough implements a pass-through resolver. It sends the target
-// name without scheme back to gRPC as resolved address.
-package passthrough
-
-import "google.golang.org/grpc/resolver"
-
-const scheme = "passthrough"
-
-type passthroughBuilder struct{}
-
-func (*passthroughBuilder) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOption) (resolver.Resolver, error) {
-	r := &passthroughResolver{
-		target: target,
-		cc:     cc,
-	}
-	r.start()
-	return r, nil
-}
-
-func (*passthroughBuilder) Scheme() string {
-	return scheme
-}
-
-type passthroughResolver struct {
-	target resolver.Target
-	cc     resolver.ClientConn
-}
-
-func (r *passthroughResolver) start() {
-	r.cc.UpdateState(resolver.State{Addresses: []resolver.Address{{Addr: r.target.Endpoint}}})
-}
-
-func (*passthroughResolver) ResolveNow(o resolver.ResolveNowOption) {}
-
-func (*passthroughResolver) Close() {}
-
-func init() {
-	resolver.Register(&passthroughBuilder{})
-}
diff --git a/vendor/google.golang.org/grpc/resolver/resolver.go b/vendor/google.golang.org/grpc/resolver/resolver.go
index e83da34..4c5423b 100644
--- a/vendor/google.golang.org/grpc/resolver/resolver.go
+++ b/vendor/google.golang.org/grpc/resolver/resolver.go
@@ -21,6 +21,10 @@
 package resolver
 
 import (
+	"context"
+	"net"
+
+	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/serviceconfig"
 )
 
@@ -86,9 +90,16 @@
 	// Type is the type of this address.
 	Type AddressType
 	// ServerName is the name of this address.
+	// If non-empty, the ServerName is used as the transport certification authority for
+	// the address, instead of the hostname from the Dial target string. In most cases,
+	// this should not be set.
 	//
-	// e.g. if Type is GRPCLB, ServerName should be the name of the remote load
+	// If Type is GRPCLB, ServerName should be the name of the remote load
 	// balancer, not the name of the backend.
+	//
+	// WARNING: ServerName must only be populated with trusted values. It
+	// is insecure to populate it with data from untrusted inputs since untrusted
+	// values could be used to bypass the authority checks performed by TLS.
 	ServerName string
 	// Metadata is the information associated with Addr, which may be used
 	// to make load balancing decision.
@@ -98,18 +109,38 @@
 // BuildOption includes additional information for the builder to create
 // the resolver.
 type BuildOption struct {
-	// DisableServiceConfig indicates whether resolver should fetch service config data.
+	// DisableServiceConfig indicates whether a resolver implementation should
+	// fetch service config data.
 	DisableServiceConfig bool
+	// DialCreds is the transport credentials used by the ClientConn for
+	// communicating with the target gRPC service (set via
+	// WithTransportCredentials). In cases where a name resolution service
+	// requires the same credentials, the resolver may use this field. In most
+	// cases though, it is not appropriate, and this field may be ignored.
+	DialCreds credentials.TransportCredentials
+	// CredsBundle is the credentials bundle used by the ClientConn for
+	// communicating with the target gRPC service (set via
+	// WithCredentialsBundle). In cases where a name resolution service
+	// requires the same credentials, the resolver may use this field. In most
+	// cases though, it is not appropriate, and this field may be ignored.
+	CredsBundle credentials.Bundle
+	// Dialer is the custom dialer used by the ClientConn for dialling the
+	// target gRPC service (set via WithDialer). In cases where a name
+	// resolution service requires the same dialer, the resolver may use this
+	// field. In most cases though, it is not appropriate, and this field may
+	// be ignored.
+	Dialer func(context.Context, string) (net.Conn, error)
 }
 
 // State contains the current Resolver state relevant to the ClientConn.
 type State struct {
-	Addresses []Address // Resolved addresses for the target
-	// ServiceConfig is the parsed service config; obtained from
-	// serviceconfig.Parse.
-	ServiceConfig serviceconfig.Config
+	// Addresses is the latest set of resolved addresses for the target.
+	Addresses []Address
 
-	// TODO: add Err error
+	// ServiceConfig contains the result from parsing the latest service
+	// config.  If it is nil, it indicates no service config is present or the
+	// resolver does not provide service configs.
+	ServiceConfig *serviceconfig.ParseResult
 }
 
 // ClientConn contains the callbacks for resolver to notify any updates
@@ -122,6 +153,10 @@
 type ClientConn interface {
 	// UpdateState updates the state of the ClientConn appropriately.
 	UpdateState(State)
+	// ReportError notifies the ClientConn that the Resolver encountered an
+	// error.  The ClientConn will notify the load balancer and begin calling
+	// ResolveNow on the Resolver with exponential backoff.
+	ReportError(error)
 	// NewAddress is called by resolver to notify ClientConn a new list
 	// of resolved addresses.
 	// The address list should be the complete list of resolved addresses.
@@ -133,6 +168,9 @@
 	//
 	// Deprecated: Use UpdateState instead.
 	NewServiceConfig(serviceConfig string)
+	// ParseServiceConfig parses the provided service config and returns an
+	// object that provides the parsed config.
+	ParseServiceConfig(serviceConfigJSON string) *serviceconfig.ParseResult
 }
 
 // Target represents a target for gRPC, as specified in: