Bump queue-worker and NATS

NATS moved its primary library to: github.com/nats-io/stan.go

This commit synchronises the library in the gateway to match the
queue worker.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

gateway/vendor/github.com/nats-io/jwt/user_claims.go

@@ -0,0 +1,99 @@
+/*
+ * Copyright 2018-2019 The NATS 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 jwt
+
+import (
+	"errors"
+
+	"github.com/nats-io/nkeys"
+)
+
+// User defines the user specific data in a user JWT
+type User struct {
+	Permissions
+	Limits
+}
+
+// Validate checks the permissions and limits in a User jwt
+func (u *User) Validate(vr *ValidationResults) {
+	u.Permissions.Validate(vr)
+	u.Limits.Validate(vr)
+}
+
+// UserClaims defines a user JWT
+type UserClaims struct {
+	ClaimsData
+	User `json:"nats,omitempty"`
+	// IssuerAccount stores the public key for the account the issuer represents.
+	// When set, the claim was issued by a signing key.
+	IssuerAccount string `json:"issuer_account,omitempty"`
+}
+
+// NewUserClaims creates a user JWT with the specific subject/public key
+func NewUserClaims(subject string) *UserClaims {
+	if subject == "" {
+		return nil
+	}
+	c := &UserClaims{}
+	c.Subject = subject
+	return c
+}
+
+// Encode tries to turn the user claims into a JWT string
+func (u *UserClaims) Encode(pair nkeys.KeyPair) (string, error) {
+	if !nkeys.IsValidPublicUserKey(u.Subject) {
+		return "", errors.New("expected subject to be user public key")
+	}
+	u.ClaimsData.Type = UserClaim
+	return u.ClaimsData.Encode(pair, u)
+}
+
+// DecodeUserClaims tries to parse a user claims from a JWT string
+func DecodeUserClaims(token string) (*UserClaims, error) {
+	v := UserClaims{}
+	if err := Decode(token, &v); err != nil {
+		return nil, err
+	}
+	return &v, nil
+}
+
+// Validate checks the generic and specific parts of the user jwt
+func (u *UserClaims) Validate(vr *ValidationResults) {
+	u.ClaimsData.Validate(vr)
+	u.User.Validate(vr)
+	if u.IssuerAccount != "" && !nkeys.IsValidPublicAccountKey(u.IssuerAccount) {
+		vr.AddError("account_id is not an account public key")
+	}
+}
+
+// ExpectedPrefixes defines the types that can encode a user JWT, account
+func (u *UserClaims) ExpectedPrefixes() []nkeys.PrefixByte {
+	return []nkeys.PrefixByte{nkeys.PrefixByteAccount}
+}
+
+// Claims returns the generic data from a user jwt
+func (u *UserClaims) Claims() *ClaimsData {
+	return &u.ClaimsData
+}
+
+// Payload returns the user specific data from a user JWT
+func (u *UserClaims) Payload() interface{} {
+	return &u.User
+}
+
+func (u *UserClaims) String() string {
+	return u.ClaimsData.String(u)
+}