diff --git a/vendor/gopkg.in/yaml.v3/yaml.go b/vendor/gopkg.in/yaml.v3/yaml.go
new file mode 100644
index 0000000..b5d35a5
--- /dev/null
+++ b/vendor/gopkg.in/yaml.v3/yaml.go
@@ -0,0 +1,662 @@
+//
+// Copyright (c) 2011-2019 Canonical Ltd
+//
+// 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 yaml implements YAML support for the Go language.
+//
+// Source code and other details for the project are available at GitHub:
+//
+//   https://github.com/go-yaml/yaml
+//
+package yaml
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"reflect"
+	"strings"
+	"sync"
+	"unicode/utf8"
+)
+
+// The Unmarshaler interface may be implemented by types to customize their
+// behavior when being unmarshaled from a YAML document.
+type Unmarshaler interface {
+	UnmarshalYAML(value *Node) error
+}
+
+type obsoleteUnmarshaler interface {
+	UnmarshalYAML(unmarshal func(interface{}) error) error
+}
+
+// The Marshaler interface may be implemented by types to customize their
+// behavior when being marshaled into a YAML document. The returned value
+// is marshaled in place of the original value implementing Marshaler.
+//
+// If an error is returned by MarshalYAML, the marshaling procedure stops
+// and returns with the provided error.
+type Marshaler interface {
+	MarshalYAML() (interface{}, error)
+}
+
+// Unmarshal decodes the first document found within the in byte slice
+// and assigns decoded values into the out value.
+//
+// Maps and pointers (to a struct, string, int, etc) are accepted as out
+// values. If an internal pointer within a struct is not initialized,
+// the yaml package will initialize it if necessary for unmarshalling
+// the provided data. The out parameter must not be nil.
+//
+// The type of the decoded values should be compatible with the respective
+// values in out. If one or more values cannot be decoded due to a type
+// mismatches, decoding continues partially until the end of the YAML
+// content, and a *yaml.TypeError is returned with details for all
+// missed values.
+//
+// Struct fields are only unmarshalled if they are exported (have an
+// upper case first letter), and are unmarshalled using the field name
+// lowercased as the default key. Custom keys may be defined via the
+// "yaml" name in the field tag: the content preceding the first comma
+// is used as the key, and the following comma-separated options are
+// used to tweak the marshalling process (see Marshal).
+// Conflicting names result in a runtime error.
+//
+// For example:
+//
+//     type T struct {
+//         F int `yaml:"a,omitempty"`
+//         B int
+//     }
+//     var t T
+//     yaml.Unmarshal([]byte("a: 1\nb: 2"), &t)
+//
+// See the documentation of Marshal for the format of tags and a list of
+// supported tag options.
+//
+func Unmarshal(in []byte, out interface{}) (err error) {
+	return unmarshal(in, out, false)
+}
+
+// A Decorder reads and decodes YAML values from an input stream.
+type Decoder struct {
+	parser      *parser
+	knownFields bool
+}
+
+// NewDecoder returns a new decoder that reads from r.
+//
+// The decoder introduces its own buffering and may read
+// data from r beyond the YAML values requested.
+func NewDecoder(r io.Reader) *Decoder {
+	return &Decoder{
+		parser: newParserFromReader(r),
+	}
+}
+
+// KnownFields ensures that the keys in decoded mappings to
+// exist as fields in the struct being decoded into.
+func (dec *Decoder) KnownFields(enable bool) {
+	dec.knownFields = enable
+}
+
+// Decode reads the next YAML-encoded value from its input
+// and stores it in the value pointed to by v.
+//
+// See the documentation for Unmarshal for details about the
+// conversion of YAML into a Go value.
+func (dec *Decoder) Decode(v interface{}) (err error) {
+	d := newDecoder()
+	d.knownFields = dec.knownFields
+	defer handleErr(&err)
+	node := dec.parser.parse()
+	if node == nil {
+		return io.EOF
+	}
+	out := reflect.ValueOf(v)
+	if out.Kind() == reflect.Ptr && !out.IsNil() {
+		out = out.Elem()
+	}
+	d.unmarshal(node, out)
+	if len(d.terrors) > 0 {
+		return &TypeError{d.terrors}
+	}
+	return nil
+}
+
+// Decode decodes the node and stores its data into the value pointed to by v.
+//
+// See the documentation for Unmarshal for details about the
+// conversion of YAML into a Go value.
+func (n *Node) Decode(v interface{}) (err error) {
+	d := newDecoder()
+	defer handleErr(&err)
+	out := reflect.ValueOf(v)
+	if out.Kind() == reflect.Ptr && !out.IsNil() {
+		out = out.Elem()
+	}
+	d.unmarshal(n, out)
+	if len(d.terrors) > 0 {
+		return &TypeError{d.terrors}
+	}
+	return nil
+}
+
+func unmarshal(in []byte, out interface{}, strict bool) (err error) {
+	defer handleErr(&err)
+	d := newDecoder()
+	p := newParser(in)
+	defer p.destroy()
+	node := p.parse()
+	if node != nil {
+		v := reflect.ValueOf(out)
+		if v.Kind() == reflect.Ptr && !v.IsNil() {
+			v = v.Elem()
+		}
+		d.unmarshal(node, v)
+	}
+	if len(d.terrors) > 0 {
+		return &TypeError{d.terrors}
+	}
+	return nil
+}
+
+// Marshal serializes the value provided into a YAML document. The structure
+// of the generated document will reflect the structure of the value itself.
+// Maps and pointers (to struct, string, int, etc) are accepted as the in value.
+//
+// Struct fields are only marshalled if they are exported (have an upper case
+// first letter), and are marshalled using the field name lowercased as the
+// default key. Custom keys may be defined via the "yaml" name in the field
+// tag: the content preceding the first comma is used as the key, and the
+// following comma-separated options are used to tweak the marshalling process.
+// Conflicting names result in a runtime error.
+//
+// The field tag format accepted is:
+//
+//     `(...) yaml:"[<key>][,<flag1>[,<flag2>]]" (...)`
+//
+// The following flags are currently supported:
+//
+//     omitempty    Only include the field if it's not set to the zero
+//                  value for the type or to empty slices or maps.
+//                  Zero valued structs will be omitted if all their public
+//                  fields are zero, unless they implement an IsZero
+//                  method (see the IsZeroer interface type), in which
+//                  case the field will be included if that method returns true.
+//
+//     flow         Marshal using a flow style (useful for structs,
+//                  sequences and maps).
+//
+//     inline       Inline the field, which must be a struct or a map,
+//                  causing all of its fields or keys to be processed as if
+//                  they were part of the outer struct. For maps, keys must
+//                  not conflict with the yaml keys of other struct fields.
+//
+// In addition, if the key is "-", the field is ignored.
+//
+// For example:
+//
+//     type T struct {
+//         F int `yaml:"a,omitempty"`
+//         B int
+//     }
+//     yaml.Marshal(&T{B: 2}) // Returns "b: 2\n"
+//     yaml.Marshal(&T{F: 1}} // Returns "a: 1\nb: 0\n"
+//
+func Marshal(in interface{}) (out []byte, err error) {
+	defer handleErr(&err)
+	e := newEncoder()
+	defer e.destroy()
+	e.marshalDoc("", reflect.ValueOf(in))
+	e.finish()
+	out = e.out
+	return
+}
+
+// An Encoder writes YAML values to an output stream.
+type Encoder struct {
+	encoder *encoder
+}
+
+// NewEncoder returns a new encoder that writes to w.
+// The Encoder should be closed after use to flush all data
+// to w.
+func NewEncoder(w io.Writer) *Encoder {
+	return &Encoder{
+		encoder: newEncoderWithWriter(w),
+	}
+}
+
+// Encode writes the YAML encoding of v to the stream.
+// If multiple items are encoded to the stream, the
+// second and subsequent document will be preceded
+// with a "---" document separator, but the first will not.
+//
+// See the documentation for Marshal for details about the conversion of Go
+// values to YAML.
+func (e *Encoder) Encode(v interface{}) (err error) {
+	defer handleErr(&err)
+	e.encoder.marshalDoc("", reflect.ValueOf(v))
+	return nil
+}
+
+// SetIndent changes the used indentation used when encoding.
+func (e *Encoder) SetIndent(spaces int) {
+	if spaces < 0 {
+		panic("yaml: cannot indent to a negative number of spaces")
+	}
+	e.encoder.indent = spaces
+}
+
+// Close closes the encoder by writing any remaining data.
+// It does not write a stream terminating string "...".
+func (e *Encoder) Close() (err error) {
+	defer handleErr(&err)
+	e.encoder.finish()
+	return nil
+}
+
+func handleErr(err *error) {
+	if v := recover(); v != nil {
+		if e, ok := v.(yamlError); ok {
+			*err = e.err
+		} else {
+			panic(v)
+		}
+	}
+}
+
+type yamlError struct {
+	err error
+}
+
+func fail(err error) {
+	panic(yamlError{err})
+}
+
+func failf(format string, args ...interface{}) {
+	panic(yamlError{fmt.Errorf("yaml: "+format, args...)})
+}
+
+// A TypeError is returned by Unmarshal when one or more fields in
+// the YAML document cannot be properly decoded into the requested
+// types. When this error is returned, the value is still
+// unmarshaled partially.
+type TypeError struct {
+	Errors []string
+}
+
+func (e *TypeError) Error() string {
+	return fmt.Sprintf("yaml: unmarshal errors:\n  %s", strings.Join(e.Errors, "\n  "))
+}
+
+type Kind uint32
+
+const (
+	DocumentNode Kind = 1 << iota
+	SequenceNode
+	MappingNode
+	ScalarNode
+	AliasNode
+)
+
+type Style uint32
+
+const (
+	TaggedStyle Style = 1 << iota
+	DoubleQuotedStyle
+	SingleQuotedStyle
+	LiteralStyle
+	FoldedStyle
+	FlowStyle
+)
+
+// Node represents an element in the YAML document hierarchy. While documents
+// are typically encoded and decoded into higher level types, such as structs
+// and maps, Node is an intermediate representation that allows detailed
+// control over the content being decoded or encoded.
+//
+// Values that make use of the Node type interact with the yaml package in the
+// same way any other type would do, by encoding and decoding yaml data
+// directly or indirectly into them.
+//
+// For example:
+//
+//     var person struct {
+//             Name    string
+//             Address yaml.Node
+//     }
+//     err := yaml.Unmarshal(data, &person)
+// 
+// Or by itself:
+//
+//     var person Node
+//     err := yaml.Unmarshal(data, &person)
+//
+type Node struct {
+	// Kind defines whether the node is a document, a mapping, a sequence,
+	// a scalar value, or an alias to another node. The specific data type of
+	// scalar nodes may be obtained via the ShortTag and LongTag methods.
+	Kind  Kind
+
+	// Style allows customizing the apperance of the node in the tree.
+	Style Style
+
+	// Tag holds the YAML tag defining the data type for the value.
+	// When decoding, this field will always be set to the resolved tag,
+	// even when it wasn't explicitly provided in the YAML content.
+	// When encoding, if this field is unset the value type will be
+	// implied from the node properties, and if it is set, it will only
+	// be serialized into the representation if TaggedStyle is used or
+	// the implicit tag diverges from the provided one.
+	Tag string
+
+	// Value holds the unescaped and unquoted represenation of the value.
+	Value string
+
+	// Anchor holds the anchor name for this node, which allows aliases to point to it.
+	Anchor string
+
+	// Alias holds the node that this alias points to. Only valid when Kind is AliasNode.
+	Alias *Node
+
+	// Content holds contained nodes for documents, mappings, and sequences.
+	Content []*Node
+
+	// HeadComment holds any comments in the lines preceding the node and
+	// not separated by an empty line.
+	HeadComment string
+
+	// LineComment holds any comments at the end of the line where the node is in.
+	LineComment string
+
+	// FootComment holds any comments following the node and before empty lines.
+	FootComment string
+
+	// Line and Column hold the node position in the decoded YAML text.
+	// These fields are not respected when encoding the node.
+	Line   int
+	Column int
+}
+
+// LongTag returns the long form of the tag that indicates the data type for
+// the node. If the Tag field isn't explicitly defined, one will be computed
+// based on the node properties.
+func (n *Node) LongTag() string {
+	return longTag(n.ShortTag())
+}
+
+// ShortTag returns the short form of the YAML tag that indicates data type for
+// the node. If the Tag field isn't explicitly defined, one will be computed
+// based on the node properties.
+func (n *Node) ShortTag() string {
+	if n.indicatedString() {
+		return strTag
+	}
+	if n.Tag == "" || n.Tag == "!" {
+		switch n.Kind {
+		case MappingNode:
+			return mapTag
+		case SequenceNode:
+			return seqTag
+		case AliasNode:
+			if n.Alias != nil {
+				return n.Alias.ShortTag()
+			}
+		case ScalarNode:
+			tag, _ := resolve("", n.Value)
+			return tag
+		}
+		return ""
+	}
+	return shortTag(n.Tag)
+}
+
+func (n *Node) indicatedString() bool {
+	return n.Kind == ScalarNode &&
+		(shortTag(n.Tag) == strTag ||
+			(n.Tag == "" || n.Tag == "!") && n.Style&(SingleQuotedStyle|DoubleQuotedStyle|LiteralStyle|FoldedStyle) != 0)
+}
+
+// SetString is a convenience function that sets the node to a string value
+// and defines its style in a pleasant way depending on its content.
+func (n *Node) SetString(s string) {
+	n.Kind = ScalarNode
+	if utf8.ValidString(s) {
+		n.Value = s
+		n.Tag = strTag
+	} else {
+		n.Value = encodeBase64(s)
+		n.Tag = binaryTag
+	}
+	if strings.Contains(n.Value, "\n") {
+		n.Style = LiteralStyle
+	}
+}
+
+// --------------------------------------------------------------------------
+// Maintain a mapping of keys to structure field indexes
+
+// The code in this section was copied from mgo/bson.
+
+// structInfo holds details for the serialization of fields of
+// a given struct.
+type structInfo struct {
+	FieldsMap  map[string]fieldInfo
+	FieldsList []fieldInfo
+
+	// InlineMap is the number of the field in the struct that
+	// contains an ,inline map, or -1 if there's none.
+	InlineMap int
+
+	// InlineUnmarshalers holds indexes to inlined fields that
+	// contain unmarshaler values.
+	InlineUnmarshalers [][]int
+}
+
+type fieldInfo struct {
+	Key       string
+	Num       int
+	OmitEmpty bool
+	Flow      bool
+	// Id holds the unique field identifier, so we can cheaply
+	// check for field duplicates without maintaining an extra map.
+	Id int
+
+	// Inline holds the field index if the field is part of an inlined struct.
+	Inline []int
+}
+
+var structMap = make(map[reflect.Type]*structInfo)
+var fieldMapMutex sync.RWMutex
+var unmarshalerType reflect.Type
+
+func init() {
+	var v Unmarshaler
+	unmarshalerType = reflect.ValueOf(&v).Elem().Type()
+}
+
+func getStructInfo(st reflect.Type) (*structInfo, error) {
+	fieldMapMutex.RLock()
+	sinfo, found := structMap[st]
+	fieldMapMutex.RUnlock()
+	if found {
+		return sinfo, nil
+	}
+
+	n := st.NumField()
+	fieldsMap := make(map[string]fieldInfo)
+	fieldsList := make([]fieldInfo, 0, n)
+	inlineMap := -1
+	inlineUnmarshalers := [][]int(nil)
+	for i := 0; i != n; i++ {
+		field := st.Field(i)
+		if field.PkgPath != "" && !field.Anonymous {
+			continue // Private field
+		}
+
+		info := fieldInfo{Num: i}
+
+		tag := field.Tag.Get("yaml")
+		if tag == "" && strings.Index(string(field.Tag), ":") < 0 {
+			tag = string(field.Tag)
+		}
+		if tag == "-" {
+			continue
+		}
+
+		inline := false
+		fields := strings.Split(tag, ",")
+		if len(fields) > 1 {
+			for _, flag := range fields[1:] {
+				switch flag {
+				case "omitempty":
+					info.OmitEmpty = true
+				case "flow":
+					info.Flow = true
+				case "inline":
+					inline = true
+				default:
+					return nil, errors.New(fmt.Sprintf("unsupported flag %q in tag %q of type %s", flag, tag, st))
+				}
+			}
+			tag = fields[0]
+		}
+
+		if inline {
+			switch field.Type.Kind() {
+			case reflect.Map:
+				if inlineMap >= 0 {
+					return nil, errors.New("multiple ,inline maps in struct " + st.String())
+				}
+				if field.Type.Key() != reflect.TypeOf("") {
+					return nil, errors.New("option ,inline needs a map with string keys in struct " + st.String())
+				}
+				inlineMap = info.Num
+			case reflect.Struct, reflect.Ptr:
+				ftype := field.Type
+				for ftype.Kind() == reflect.Ptr {
+					ftype = ftype.Elem()
+				}
+				if ftype.Kind() != reflect.Struct {
+					return nil, errors.New("option ,inline may only be used on a struct or map field")
+				}
+				if reflect.PtrTo(ftype).Implements(unmarshalerType) {
+					inlineUnmarshalers = append(inlineUnmarshalers, []int{i})
+				} else {
+					sinfo, err := getStructInfo(ftype)
+					if err != nil {
+						return nil, err
+					}
+					for _, index := range sinfo.InlineUnmarshalers {
+						inlineUnmarshalers = append(inlineUnmarshalers, append([]int{i}, index...))
+					}
+					for _, finfo := range sinfo.FieldsList {
+						if _, found := fieldsMap[finfo.Key]; found {
+							msg := "duplicated key '" + finfo.Key + "' in struct " + st.String()
+							return nil, errors.New(msg)
+						}
+						if finfo.Inline == nil {
+							finfo.Inline = []int{i, finfo.Num}
+						} else {
+							finfo.Inline = append([]int{i}, finfo.Inline...)
+						}
+						finfo.Id = len(fieldsList)
+						fieldsMap[finfo.Key] = finfo
+						fieldsList = append(fieldsList, finfo)
+					}
+				}
+			default:
+				return nil, errors.New("option ,inline may only be used on a struct or map field")
+			}
+			continue
+		}
+
+		if tag != "" {
+			info.Key = tag
+		} else {
+			info.Key = strings.ToLower(field.Name)
+		}
+
+		if _, found = fieldsMap[info.Key]; found {
+			msg := "duplicated key '" + info.Key + "' in struct " + st.String()
+			return nil, errors.New(msg)
+		}
+
+		info.Id = len(fieldsList)
+		fieldsList = append(fieldsList, info)
+		fieldsMap[info.Key] = info
+	}
+
+	sinfo = &structInfo{
+		FieldsMap:          fieldsMap,
+		FieldsList:         fieldsList,
+		InlineMap:          inlineMap,
+		InlineUnmarshalers: inlineUnmarshalers,
+	}
+
+	fieldMapMutex.Lock()
+	structMap[st] = sinfo
+	fieldMapMutex.Unlock()
+	return sinfo, nil
+}
+
+// IsZeroer is used to check whether an object is zero to
+// determine whether it should be omitted when marshaling
+// with the omitempty flag. One notable implementation
+// is time.Time.
+type IsZeroer interface {
+	IsZero() bool
+}
+
+func isZero(v reflect.Value) bool {
+	kind := v.Kind()
+	if z, ok := v.Interface().(IsZeroer); ok {
+		if (kind == reflect.Ptr || kind == reflect.Interface) && v.IsNil() {
+			return true
+		}
+		return z.IsZero()
+	}
+	switch kind {
+	case reflect.String:
+		return len(v.String()) == 0
+	case reflect.Interface, reflect.Ptr:
+		return v.IsNil()
+	case reflect.Slice:
+		return v.Len() == 0
+	case reflect.Map:
+		return v.Len() == 0
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return v.Int() == 0
+	case reflect.Float32, reflect.Float64:
+		return v.Float() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return v.Uint() == 0
+	case reflect.Bool:
+		return !v.Bool()
+	case reflect.Struct:
+		vt := v.Type()
+		for i := v.NumField() - 1; i >= 0; i-- {
+			if vt.Field(i).PkgPath != "" {
+				continue // Private field
+			}
+			if !isZero(v.Field(i)) {
+				return false
+			}
+		}
+		return true
+	}
+	return false
+}