diff --git a/vendor/golang.org/x/text/language/language.go b/vendor/golang.org/x/text/language/language.go
new file mode 100644
index 0000000..abfa17f
--- /dev/null
+++ b/vendor/golang.org/x/text/language/language.go
@@ -0,0 +1,601 @@
+// Copyright 2013 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.
+
+//go:generate go run gen.go -output tables.go
+
+package language
+
+// TODO: Remove above NOTE after:
+// - verifying that tables are dropped correctly (most notably matcher tables).
+
+import (
+	"strings"
+
+	"golang.org/x/text/internal/language"
+	"golang.org/x/text/internal/language/compact"
+)
+
+// Tag represents a BCP 47 language tag. It is used to specify an instance of a
+// specific language or locale. All language tag values are guaranteed to be
+// well-formed.
+type Tag compact.Tag
+
+func makeTag(t language.Tag) (tag Tag) {
+	return Tag(compact.Make(t))
+}
+
+func (t *Tag) tag() language.Tag {
+	return (*compact.Tag)(t).Tag()
+}
+
+func (t *Tag) isCompact() bool {
+	return (*compact.Tag)(t).IsCompact()
+}
+
+// TODO: improve performance.
+func (t *Tag) lang() language.Language { return t.tag().LangID }
+func (t *Tag) region() language.Region { return t.tag().RegionID }
+func (t *Tag) script() language.Script { return t.tag().ScriptID }
+
+// Make is a convenience wrapper for Parse that omits the error.
+// In case of an error, a sensible default is returned.
+func Make(s string) Tag {
+	return Default.Make(s)
+}
+
+// Make is a convenience wrapper for c.Parse that omits the error.
+// In case of an error, a sensible default is returned.
+func (c CanonType) Make(s string) Tag {
+	t, _ := c.Parse(s)
+	return t
+}
+
+// Raw returns the raw base language, script and region, without making an
+// attempt to infer their values.
+func (t Tag) Raw() (b Base, s Script, r Region) {
+	tt := t.tag()
+	return Base{tt.LangID}, Script{tt.ScriptID}, Region{tt.RegionID}
+}
+
+// IsRoot returns true if t is equal to language "und".
+func (t Tag) IsRoot() bool {
+	return compact.Tag(t).IsRoot()
+}
+
+// CanonType can be used to enable or disable various types of canonicalization.
+type CanonType int
+
+const (
+	// Replace deprecated base languages with their preferred replacements.
+	DeprecatedBase CanonType = 1 << iota
+	// Replace deprecated scripts with their preferred replacements.
+	DeprecatedScript
+	// Replace deprecated regions with their preferred replacements.
+	DeprecatedRegion
+	// Remove redundant scripts.
+	SuppressScript
+	// Normalize legacy encodings. This includes legacy languages defined in
+	// CLDR as well as bibliographic codes defined in ISO-639.
+	Legacy
+	// Map the dominant language of a macro language group to the macro language
+	// subtag. For example cmn -> zh.
+	Macro
+	// The CLDR flag should be used if full compatibility with CLDR is required.
+	// There are a few cases where language.Tag may differ from CLDR. To follow all
+	// of CLDR's suggestions, use All|CLDR.
+	CLDR
+
+	// Raw can be used to Compose or Parse without Canonicalization.
+	Raw CanonType = 0
+
+	// Replace all deprecated tags with their preferred replacements.
+	Deprecated = DeprecatedBase | DeprecatedScript | DeprecatedRegion
+
+	// All canonicalizations recommended by BCP 47.
+	BCP47 = Deprecated | SuppressScript
+
+	// All canonicalizations.
+	All = BCP47 | Legacy | Macro
+
+	// Default is the canonicalization used by Parse, Make and Compose. To
+	// preserve as much information as possible, canonicalizations that remove
+	// potentially valuable information are not included. The Matcher is
+	// designed to recognize similar tags that would be the same if
+	// they were canonicalized using All.
+	Default = Deprecated | Legacy
+
+	canonLang = DeprecatedBase | Legacy | Macro
+
+	// TODO: LikelyScript, LikelyRegion: suppress similar to ICU.
+)
+
+// canonicalize returns the canonicalized equivalent of the tag and
+// whether there was any change.
+func canonicalize(c CanonType, t language.Tag) (language.Tag, bool) {
+	if c == Raw {
+		return t, false
+	}
+	changed := false
+	if c&SuppressScript != 0 {
+		if t.LangID.SuppressScript() == t.ScriptID {
+			t.ScriptID = 0
+			changed = true
+		}
+	}
+	if c&canonLang != 0 {
+		for {
+			if l, aliasType := t.LangID.Canonicalize(); l != t.LangID {
+				switch aliasType {
+				case language.Legacy:
+					if c&Legacy != 0 {
+						if t.LangID == _sh && t.ScriptID == 0 {
+							t.ScriptID = _Latn
+						}
+						t.LangID = l
+						changed = true
+					}
+				case language.Macro:
+					if c&Macro != 0 {
+						// We deviate here from CLDR. The mapping "nb" -> "no"
+						// qualifies as a typical Macro language mapping.  However,
+						// for legacy reasons, CLDR maps "no", the macro language
+						// code for Norwegian, to the dominant variant "nb". This
+						// change is currently under consideration for CLDR as well.
+						// See https://unicode.org/cldr/trac/ticket/2698 and also
+						// https://unicode.org/cldr/trac/ticket/1790 for some of the
+						// practical implications. TODO: this check could be removed
+						// if CLDR adopts this change.
+						if c&CLDR == 0 || t.LangID != _nb {
+							changed = true
+							t.LangID = l
+						}
+					}
+				case language.Deprecated:
+					if c&DeprecatedBase != 0 {
+						if t.LangID == _mo && t.RegionID == 0 {
+							t.RegionID = _MD
+						}
+						t.LangID = l
+						changed = true
+						// Other canonicalization types may still apply.
+						continue
+					}
+				}
+			} else if c&Legacy != 0 && t.LangID == _no && c&CLDR != 0 {
+				t.LangID = _nb
+				changed = true
+			}
+			break
+		}
+	}
+	if c&DeprecatedScript != 0 {
+		if t.ScriptID == _Qaai {
+			changed = true
+			t.ScriptID = _Zinh
+		}
+	}
+	if c&DeprecatedRegion != 0 {
+		if r := t.RegionID.Canonicalize(); r != t.RegionID {
+			changed = true
+			t.RegionID = r
+		}
+	}
+	return t, changed
+}
+
+// Canonicalize returns the canonicalized equivalent of the tag.
+func (c CanonType) Canonicalize(t Tag) (Tag, error) {
+	// First try fast path.
+	if t.isCompact() {
+		if _, changed := canonicalize(c, compact.Tag(t).Tag()); !changed {
+			return t, nil
+		}
+	}
+	// It is unlikely that one will canonicalize a tag after matching. So do
+	// a slow but simple approach here.
+	if tag, changed := canonicalize(c, t.tag()); changed {
+		tag.RemakeString()
+		return makeTag(tag), nil
+	}
+	return t, nil
+
+}
+
+// Confidence indicates the level of certainty for a given return value.
+// For example, Serbian may be written in Cyrillic or Latin script.
+// The confidence level indicates whether a value was explicitly specified,
+// whether it is typically the only possible value, or whether there is
+// an ambiguity.
+type Confidence int
+
+const (
+	No    Confidence = iota // full confidence that there was no match
+	Low                     // most likely value picked out of a set of alternatives
+	High                    // value is generally assumed to be the correct match
+	Exact                   // exact match or explicitly specified value
+)
+
+var confName = []string{"No", "Low", "High", "Exact"}
+
+func (c Confidence) String() string {
+	return confName[c]
+}
+
+// String returns the canonical string representation of the language tag.
+func (t Tag) String() string {
+	return t.tag().String()
+}
+
+// MarshalText implements encoding.TextMarshaler.
+func (t Tag) MarshalText() (text []byte, err error) {
+	return t.tag().MarshalText()
+}
+
+// UnmarshalText implements encoding.TextUnmarshaler.
+func (t *Tag) UnmarshalText(text []byte) error {
+	var tag language.Tag
+	err := tag.UnmarshalText(text)
+	*t = makeTag(tag)
+	return err
+}
+
+// Base returns the base language of the language tag. If the base language is
+// unspecified, an attempt will be made to infer it from the context.
+// It uses a variant of CLDR's Add Likely Subtags algorithm. This is subject to change.
+func (t Tag) Base() (Base, Confidence) {
+	if b := t.lang(); b != 0 {
+		return Base{b}, Exact
+	}
+	tt := t.tag()
+	c := High
+	if tt.ScriptID == 0 && !tt.RegionID.IsCountry() {
+		c = Low
+	}
+	if tag, err := tt.Maximize(); err == nil && tag.LangID != 0 {
+		return Base{tag.LangID}, c
+	}
+	return Base{0}, No
+}
+
+// Script infers the script for the language tag. If it was not explicitly given, it will infer
+// a most likely candidate.
+// If more than one script is commonly used for a language, the most likely one
+// is returned with a low confidence indication. For example, it returns (Cyrl, Low)
+// for Serbian.
+// If a script cannot be inferred (Zzzz, No) is returned. We do not use Zyyy (undetermined)
+// as one would suspect from the IANA registry for BCP 47. In a Unicode context Zyyy marks
+// common characters (like 1, 2, 3, '.', etc.) and is therefore more like multiple scripts.
+// See https://www.unicode.org/reports/tr24/#Values for more details. Zzzz is also used for
+// unknown value in CLDR.  (Zzzz, Exact) is returned if Zzzz was explicitly specified.
+// Note that an inferred script is never guaranteed to be the correct one. Latin is
+// almost exclusively used for Afrikaans, but Arabic has been used for some texts
+// in the past.  Also, the script that is commonly used may change over time.
+// It uses a variant of CLDR's Add Likely Subtags algorithm. This is subject to change.
+func (t Tag) Script() (Script, Confidence) {
+	if scr := t.script(); scr != 0 {
+		return Script{scr}, Exact
+	}
+	tt := t.tag()
+	sc, c := language.Script(_Zzzz), No
+	if scr := tt.LangID.SuppressScript(); scr != 0 {
+		// Note: it is not always the case that a language with a suppress
+		// script value is only written in one script (e.g. kk, ms, pa).
+		if tt.RegionID == 0 {
+			return Script{scr}, High
+		}
+		sc, c = scr, High
+	}
+	if tag, err := tt.Maximize(); err == nil {
+		if tag.ScriptID != sc {
+			sc, c = tag.ScriptID, Low
+		}
+	} else {
+		tt, _ = canonicalize(Deprecated|Macro, tt)
+		if tag, err := tt.Maximize(); err == nil && tag.ScriptID != sc {
+			sc, c = tag.ScriptID, Low
+		}
+	}
+	return Script{sc}, c
+}
+
+// Region returns the region for the language tag. If it was not explicitly given, it will
+// infer a most likely candidate from the context.
+// It uses a variant of CLDR's Add Likely Subtags algorithm. This is subject to change.
+func (t Tag) Region() (Region, Confidence) {
+	if r := t.region(); r != 0 {
+		return Region{r}, Exact
+	}
+	tt := t.tag()
+	if tt, err := tt.Maximize(); err == nil {
+		return Region{tt.RegionID}, Low // TODO: differentiate between high and low.
+	}
+	tt, _ = canonicalize(Deprecated|Macro, tt)
+	if tag, err := tt.Maximize(); err == nil {
+		return Region{tag.RegionID}, Low
+	}
+	return Region{_ZZ}, No // TODO: return world instead of undetermined?
+}
+
+// Variants returns the variants specified explicitly for this language tag.
+// or nil if no variant was specified.
+func (t Tag) Variants() []Variant {
+	if !compact.Tag(t).MayHaveVariants() {
+		return nil
+	}
+	v := []Variant{}
+	x, str := "", t.tag().Variants()
+	for str != "" {
+		x, str = nextToken(str)
+		v = append(v, Variant{x})
+	}
+	return v
+}
+
+// Parent returns the CLDR parent of t. In CLDR, missing fields in data for a
+// specific language are substituted with fields from the parent language.
+// The parent for a language may change for newer versions of CLDR.
+//
+// Parent returns a tag for a less specific language that is mutually
+// intelligible or Und if there is no such language. This may not be the same as
+// simply stripping the last BCP 47 subtag. For instance, the parent of "zh-TW"
+// is "zh-Hant", and the parent of "zh-Hant" is "und".
+func (t Tag) Parent() Tag {
+	return Tag(compact.Tag(t).Parent())
+}
+
+// returns token t and the rest of the string.
+func nextToken(s string) (t, tail string) {
+	p := strings.Index(s[1:], "-")
+	if p == -1 {
+		return s[1:], ""
+	}
+	p++
+	return s[1:p], s[p:]
+}
+
+// Extension is a single BCP 47 extension.
+type Extension struct {
+	s string
+}
+
+// String returns the string representation of the extension, including the
+// type tag.
+func (e Extension) String() string {
+	return e.s
+}
+
+// ParseExtension parses s as an extension and returns it on success.
+func ParseExtension(s string) (e Extension, err error) {
+	ext, err := language.ParseExtension(s)
+	return Extension{ext}, err
+}
+
+// Type returns the one-byte extension type of e. It returns 0 for the zero
+// exception.
+func (e Extension) Type() byte {
+	if e.s == "" {
+		return 0
+	}
+	return e.s[0]
+}
+
+// Tokens returns the list of tokens of e.
+func (e Extension) Tokens() []string {
+	return strings.Split(e.s, "-")
+}
+
+// Extension returns the extension of type x for tag t. It will return
+// false for ok if t does not have the requested extension. The returned
+// extension will be invalid in this case.
+func (t Tag) Extension(x byte) (ext Extension, ok bool) {
+	if !compact.Tag(t).MayHaveExtensions() {
+		return Extension{}, false
+	}
+	e, ok := t.tag().Extension(x)
+	return Extension{e}, ok
+}
+
+// Extensions returns all extensions of t.
+func (t Tag) Extensions() []Extension {
+	if !compact.Tag(t).MayHaveExtensions() {
+		return nil
+	}
+	e := []Extension{}
+	for _, ext := range t.tag().Extensions() {
+		e = append(e, Extension{ext})
+	}
+	return e
+}
+
+// TypeForKey returns the type associated with the given key, where key and type
+// are of the allowed values defined for the Unicode locale extension ('u') in
+// https://www.unicode.org/reports/tr35/#Unicode_Language_and_Locale_Identifiers.
+// TypeForKey will traverse the inheritance chain to get the correct value.
+func (t Tag) TypeForKey(key string) string {
+	if !compact.Tag(t).MayHaveExtensions() {
+		if key != "rg" && key != "va" {
+			return ""
+		}
+	}
+	return t.tag().TypeForKey(key)
+}
+
+// SetTypeForKey returns a new Tag with the key set to type, where key and type
+// are of the allowed values defined for the Unicode locale extension ('u') in
+// https://www.unicode.org/reports/tr35/#Unicode_Language_and_Locale_Identifiers.
+// An empty value removes an existing pair with the same key.
+func (t Tag) SetTypeForKey(key, value string) (Tag, error) {
+	tt, err := t.tag().SetTypeForKey(key, value)
+	return makeTag(tt), err
+}
+
+// NumCompactTags is the number of compact tags. The maximum tag is
+// NumCompactTags-1.
+const NumCompactTags = compact.NumCompactTags
+
+// CompactIndex returns an index, where 0 <= index < NumCompactTags, for tags
+// for which data exists in the text repository.The index will change over time
+// and should not be stored in persistent storage. If t does not match a compact
+// index, exact will be false and the compact index will be returned for the
+// first match after repeatedly taking the Parent of t.
+func CompactIndex(t Tag) (index int, exact bool) {
+	id, exact := compact.LanguageID(compact.Tag(t))
+	return int(id), exact
+}
+
+var root = language.Tag{}
+
+// Base is an ISO 639 language code, used for encoding the base language
+// of a language tag.
+type Base struct {
+	langID language.Language
+}
+
+// ParseBase parses a 2- or 3-letter ISO 639 code.
+// It returns a ValueError if s is a well-formed but unknown language identifier
+// or another error if another error occurred.
+func ParseBase(s string) (Base, error) {
+	l, err := language.ParseBase(s)
+	return Base{l}, err
+}
+
+// String returns the BCP 47 representation of the base language.
+func (b Base) String() string {
+	return b.langID.String()
+}
+
+// ISO3 returns the ISO 639-3 language code.
+func (b Base) ISO3() string {
+	return b.langID.ISO3()
+}
+
+// IsPrivateUse reports whether this language code is reserved for private use.
+func (b Base) IsPrivateUse() bool {
+	return b.langID.IsPrivateUse()
+}
+
+// Script is a 4-letter ISO 15924 code for representing scripts.
+// It is idiomatically represented in title case.
+type Script struct {
+	scriptID language.Script
+}
+
+// ParseScript parses a 4-letter ISO 15924 code.
+// It returns a ValueError if s is a well-formed but unknown script identifier
+// or another error if another error occurred.
+func ParseScript(s string) (Script, error) {
+	sc, err := language.ParseScript(s)
+	return Script{sc}, err
+}
+
+// String returns the script code in title case.
+// It returns "Zzzz" for an unspecified script.
+func (s Script) String() string {
+	return s.scriptID.String()
+}
+
+// IsPrivateUse reports whether this script code is reserved for private use.
+func (s Script) IsPrivateUse() bool {
+	return s.scriptID.IsPrivateUse()
+}
+
+// Region is an ISO 3166-1 or UN M.49 code for representing countries and regions.
+type Region struct {
+	regionID language.Region
+}
+
+// EncodeM49 returns the Region for the given UN M.49 code.
+// It returns an error if r is not a valid code.
+func EncodeM49(r int) (Region, error) {
+	rid, err := language.EncodeM49(r)
+	return Region{rid}, err
+}
+
+// ParseRegion parses a 2- or 3-letter ISO 3166-1 or a UN M.49 code.
+// It returns a ValueError if s is a well-formed but unknown region identifier
+// or another error if another error occurred.
+func ParseRegion(s string) (Region, error) {
+	r, err := language.ParseRegion(s)
+	return Region{r}, err
+}
+
+// String returns the BCP 47 representation for the region.
+// It returns "ZZ" for an unspecified region.
+func (r Region) String() string {
+	return r.regionID.String()
+}
+
+// ISO3 returns the 3-letter ISO code of r.
+// Note that not all regions have a 3-letter ISO code.
+// In such cases this method returns "ZZZ".
+func (r Region) ISO3() string {
+	return r.regionID.ISO3()
+}
+
+// M49 returns the UN M.49 encoding of r, or 0 if this encoding
+// is not defined for r.
+func (r Region) M49() int {
+	return r.regionID.M49()
+}
+
+// IsPrivateUse reports whether r has the ISO 3166 User-assigned status. This
+// may include private-use tags that are assigned by CLDR and used in this
+// implementation. So IsPrivateUse and IsCountry can be simultaneously true.
+func (r Region) IsPrivateUse() bool {
+	return r.regionID.IsPrivateUse()
+}
+
+// IsCountry returns whether this region is a country or autonomous area. This
+// includes non-standard definitions from CLDR.
+func (r Region) IsCountry() bool {
+	return r.regionID.IsCountry()
+}
+
+// IsGroup returns whether this region defines a collection of regions. This
+// includes non-standard definitions from CLDR.
+func (r Region) IsGroup() bool {
+	return r.regionID.IsGroup()
+}
+
+// Contains returns whether Region c is contained by Region r. It returns true
+// if c == r.
+func (r Region) Contains(c Region) bool {
+	return r.regionID.Contains(c.regionID)
+}
+
+// TLD returns the country code top-level domain (ccTLD). UK is returned for GB.
+// In all other cases it returns either the region itself or an error.
+//
+// This method may return an error for a region for which there exists a
+// canonical form with a ccTLD. To get that ccTLD canonicalize r first. The
+// region will already be canonicalized it was obtained from a Tag that was
+// obtained using any of the default methods.
+func (r Region) TLD() (Region, error) {
+	tld, err := r.regionID.TLD()
+	return Region{tld}, err
+}
+
+// Canonicalize returns the region or a possible replacement if the region is
+// deprecated. It will not return a replacement for deprecated regions that
+// are split into multiple regions.
+func (r Region) Canonicalize() Region {
+	return Region{r.regionID.Canonicalize()}
+}
+
+// Variant represents a registered variant of a language as defined by BCP 47.
+type Variant struct {
+	variant string
+}
+
+// ParseVariant parses and returns a Variant. An error is returned if s is not
+// a valid variant.
+func ParseVariant(s string) (Variant, error) {
+	v, err := language.ParseVariant(s)
+	return Variant{v.String()}, err
+}
+
+// String returns the string representation of the variant.
+func (v Variant) String() string {
+	return v.variant
+}