diff --git a/vendor/google.golang.org/protobuf/encoding/protojson/encode.go b/vendor/google.golang.org/protobuf/encoding/protojson/encode.go
new file mode 100644
index 0000000..ba971f0
--- /dev/null
+++ b/vendor/google.golang.org/protobuf/encoding/protojson/encode.go
@@ -0,0 +1,344 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package protojson
+
+import (
+	"encoding/base64"
+	"fmt"
+
+	"google.golang.org/protobuf/internal/encoding/json"
+	"google.golang.org/protobuf/internal/encoding/messageset"
+	"google.golang.org/protobuf/internal/errors"
+	"google.golang.org/protobuf/internal/filedesc"
+	"google.golang.org/protobuf/internal/flags"
+	"google.golang.org/protobuf/internal/genid"
+	"google.golang.org/protobuf/internal/order"
+	"google.golang.org/protobuf/internal/pragma"
+	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/reflect/protoreflect"
+	pref "google.golang.org/protobuf/reflect/protoreflect"
+	"google.golang.org/protobuf/reflect/protoregistry"
+)
+
+const defaultIndent = "  "
+
+// Format formats the message as a multiline string.
+// This function is only intended for human consumption and ignores errors.
+// Do not depend on the output being stable. It may change over time across
+// different versions of the program.
+func Format(m proto.Message) string {
+	return MarshalOptions{Multiline: true}.Format(m)
+}
+
+// Marshal writes the given proto.Message in JSON format using default options.
+// Do not depend on the output being stable. It may change over time across
+// different versions of the program.
+func Marshal(m proto.Message) ([]byte, error) {
+	return MarshalOptions{}.Marshal(m)
+}
+
+// MarshalOptions is a configurable JSON format marshaler.
+type MarshalOptions struct {
+	pragma.NoUnkeyedLiterals
+
+	// Multiline specifies whether the marshaler should format the output in
+	// indented-form with every textual element on a new line.
+	// If Indent is an empty string, then an arbitrary indent is chosen.
+	Multiline bool
+
+	// Indent specifies the set of indentation characters to use in a multiline
+	// formatted output such that every entry is preceded by Indent and
+	// terminated by a newline. If non-empty, then Multiline is treated as true.
+	// Indent can only be composed of space or tab characters.
+	Indent string
+
+	// AllowPartial allows messages that have missing required fields to marshal
+	// without returning an error. If AllowPartial is false (the default),
+	// Marshal will return error if there are any missing required fields.
+	AllowPartial bool
+
+	// UseProtoNames uses proto field name instead of lowerCamelCase name in JSON
+	// field names.
+	UseProtoNames bool
+
+	// UseEnumNumbers emits enum values as numbers.
+	UseEnumNumbers bool
+
+	// EmitUnpopulated specifies whether to emit unpopulated fields. It does not
+	// emit unpopulated oneof fields or unpopulated extension fields.
+	// The JSON value emitted for unpopulated fields are as follows:
+	//  ╔═══════╤════════════════════════════╗
+	//  ║ JSON  │ Protobuf field             ║
+	//  ╠═══════╪════════════════════════════╣
+	//  ║ false │ proto3 boolean fields      ║
+	//  ║ 0     │ proto3 numeric fields      ║
+	//  ║ ""    │ proto3 string/bytes fields ║
+	//  ║ null  │ proto2 scalar fields       ║
+	//  ║ null  │ message fields             ║
+	//  ║ []    │ list fields                ║
+	//  ║ {}    │ map fields                 ║
+	//  ╚═══════╧════════════════════════════╝
+	EmitUnpopulated bool
+
+	// Resolver is used for looking up types when expanding google.protobuf.Any
+	// messages. If nil, this defaults to using protoregistry.GlobalTypes.
+	Resolver interface {
+		protoregistry.ExtensionTypeResolver
+		protoregistry.MessageTypeResolver
+	}
+}
+
+// Format formats the message as a string.
+// This method is only intended for human consumption and ignores errors.
+// Do not depend on the output being stable. It may change over time across
+// different versions of the program.
+func (o MarshalOptions) Format(m proto.Message) string {
+	if m == nil || !m.ProtoReflect().IsValid() {
+		return "<nil>" // invalid syntax, but okay since this is for debugging
+	}
+	o.AllowPartial = true
+	b, _ := o.Marshal(m)
+	return string(b)
+}
+
+// Marshal marshals the given proto.Message in the JSON format using options in
+// MarshalOptions. Do not depend on the output being stable. It may change over
+// time across different versions of the program.
+func (o MarshalOptions) Marshal(m proto.Message) ([]byte, error) {
+	return o.marshal(m)
+}
+
+// marshal is a centralized function that all marshal operations go through.
+// For profiling purposes, avoid changing the name of this function or
+// introducing other code paths for marshal that do not go through this.
+func (o MarshalOptions) marshal(m proto.Message) ([]byte, error) {
+	if o.Multiline && o.Indent == "" {
+		o.Indent = defaultIndent
+	}
+	if o.Resolver == nil {
+		o.Resolver = protoregistry.GlobalTypes
+	}
+
+	internalEnc, err := json.NewEncoder(o.Indent)
+	if err != nil {
+		return nil, err
+	}
+
+	// Treat nil message interface as an empty message,
+	// in which case the output in an empty JSON object.
+	if m == nil {
+		return []byte("{}"), nil
+	}
+
+	enc := encoder{internalEnc, o}
+	if err := enc.marshalMessage(m.ProtoReflect(), ""); err != nil {
+		return nil, err
+	}
+	if o.AllowPartial {
+		return enc.Bytes(), nil
+	}
+	return enc.Bytes(), proto.CheckInitialized(m)
+}
+
+type encoder struct {
+	*json.Encoder
+	opts MarshalOptions
+}
+
+// typeFieldDesc is a synthetic field descriptor used for the "@type" field.
+var typeFieldDesc = func() protoreflect.FieldDescriptor {
+	var fd filedesc.Field
+	fd.L0.FullName = "@type"
+	fd.L0.Index = -1
+	fd.L1.Cardinality = protoreflect.Optional
+	fd.L1.Kind = protoreflect.StringKind
+	return &fd
+}()
+
+// typeURLFieldRanger wraps a protoreflect.Message and modifies its Range method
+// to additionally iterate over a synthetic field for the type URL.
+type typeURLFieldRanger struct {
+	order.FieldRanger
+	typeURL string
+}
+
+func (m typeURLFieldRanger) Range(f func(pref.FieldDescriptor, pref.Value) bool) {
+	if !f(typeFieldDesc, pref.ValueOfString(m.typeURL)) {
+		return
+	}
+	m.FieldRanger.Range(f)
+}
+
+// unpopulatedFieldRanger wraps a protoreflect.Message and modifies its Range
+// method to additionally iterate over unpopulated fields.
+type unpopulatedFieldRanger struct{ pref.Message }
+
+func (m unpopulatedFieldRanger) Range(f func(pref.FieldDescriptor, pref.Value) bool) {
+	fds := m.Descriptor().Fields()
+	for i := 0; i < fds.Len(); i++ {
+		fd := fds.Get(i)
+		if m.Has(fd) || fd.ContainingOneof() != nil {
+			continue // ignore populated fields and fields within a oneofs
+		}
+
+		v := m.Get(fd)
+		isProto2Scalar := fd.Syntax() == pref.Proto2 && fd.Default().IsValid()
+		isSingularMessage := fd.Cardinality() != pref.Repeated && fd.Message() != nil
+		if isProto2Scalar || isSingularMessage {
+			v = pref.Value{} // use invalid value to emit null
+		}
+		if !f(fd, v) {
+			return
+		}
+	}
+	m.Message.Range(f)
+}
+
+// marshalMessage marshals the fields in the given protoreflect.Message.
+// If the typeURL is non-empty, then a synthetic "@type" field is injected
+// containing the URL as the value.
+func (e encoder) marshalMessage(m pref.Message, typeURL string) error {
+	if !flags.ProtoLegacy && messageset.IsMessageSet(m.Descriptor()) {
+		return errors.New("no support for proto1 MessageSets")
+	}
+
+	if marshal := wellKnownTypeMarshaler(m.Descriptor().FullName()); marshal != nil {
+		return marshal(e, m)
+	}
+
+	e.StartObject()
+	defer e.EndObject()
+
+	var fields order.FieldRanger = m
+	if e.opts.EmitUnpopulated {
+		fields = unpopulatedFieldRanger{m}
+	}
+	if typeURL != "" {
+		fields = typeURLFieldRanger{fields, typeURL}
+	}
+
+	var err error
+	order.RangeFields(fields, order.IndexNameFieldOrder, func(fd pref.FieldDescriptor, v pref.Value) bool {
+		name := fd.JSONName()
+		if e.opts.UseProtoNames {
+			name = fd.TextName()
+		}
+
+		if err = e.WriteName(name); err != nil {
+			return false
+		}
+		if err = e.marshalValue(v, fd); err != nil {
+			return false
+		}
+		return true
+	})
+	return err
+}
+
+// marshalValue marshals the given protoreflect.Value.
+func (e encoder) marshalValue(val pref.Value, fd pref.FieldDescriptor) error {
+	switch {
+	case fd.IsList():
+		return e.marshalList(val.List(), fd)
+	case fd.IsMap():
+		return e.marshalMap(val.Map(), fd)
+	default:
+		return e.marshalSingular(val, fd)
+	}
+}
+
+// marshalSingular marshals the given non-repeated field value. This includes
+// all scalar types, enums, messages, and groups.
+func (e encoder) marshalSingular(val pref.Value, fd pref.FieldDescriptor) error {
+	if !val.IsValid() {
+		e.WriteNull()
+		return nil
+	}
+
+	switch kind := fd.Kind(); kind {
+	case pref.BoolKind:
+		e.WriteBool(val.Bool())
+
+	case pref.StringKind:
+		if e.WriteString(val.String()) != nil {
+			return errors.InvalidUTF8(string(fd.FullName()))
+		}
+
+	case pref.Int32Kind, pref.Sint32Kind, pref.Sfixed32Kind:
+		e.WriteInt(val.Int())
+
+	case pref.Uint32Kind, pref.Fixed32Kind:
+		e.WriteUint(val.Uint())
+
+	case pref.Int64Kind, pref.Sint64Kind, pref.Uint64Kind,
+		pref.Sfixed64Kind, pref.Fixed64Kind:
+		// 64-bit integers are written out as JSON string.
+		e.WriteString(val.String())
+
+	case pref.FloatKind:
+		// Encoder.WriteFloat handles the special numbers NaN and infinites.
+		e.WriteFloat(val.Float(), 32)
+
+	case pref.DoubleKind:
+		// Encoder.WriteFloat handles the special numbers NaN and infinites.
+		e.WriteFloat(val.Float(), 64)
+
+	case pref.BytesKind:
+		e.WriteString(base64.StdEncoding.EncodeToString(val.Bytes()))
+
+	case pref.EnumKind:
+		if fd.Enum().FullName() == genid.NullValue_enum_fullname {
+			e.WriteNull()
+		} else {
+			desc := fd.Enum().Values().ByNumber(val.Enum())
+			if e.opts.UseEnumNumbers || desc == nil {
+				e.WriteInt(int64(val.Enum()))
+			} else {
+				e.WriteString(string(desc.Name()))
+			}
+		}
+
+	case pref.MessageKind, pref.GroupKind:
+		if err := e.marshalMessage(val.Message(), ""); err != nil {
+			return err
+		}
+
+	default:
+		panic(fmt.Sprintf("%v has unknown kind: %v", fd.FullName(), kind))
+	}
+	return nil
+}
+
+// marshalList marshals the given protoreflect.List.
+func (e encoder) marshalList(list pref.List, fd pref.FieldDescriptor) error {
+	e.StartArray()
+	defer e.EndArray()
+
+	for i := 0; i < list.Len(); i++ {
+		item := list.Get(i)
+		if err := e.marshalSingular(item, fd); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// marshalMap marshals given protoreflect.Map.
+func (e encoder) marshalMap(mmap pref.Map, fd pref.FieldDescriptor) error {
+	e.StartObject()
+	defer e.EndObject()
+
+	var err error
+	order.RangeEntries(mmap, order.GenericKeyOrder, func(k pref.MapKey, v pref.Value) bool {
+		if err = e.WriteName(k.String()); err != nil {
+			return false
+		}
+		if err = e.marshalSingular(v, fd.MapValue()); err != nil {
+			return false
+		}
+		return true
+	})
+	return err
+}