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/validation.go

@@ -0,0 +1,107 @@
+/*
+ * Copyright 2018 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"
+	"fmt"
+)
+
+// ValidationIssue represents an issue during JWT validation, it may or may not be a blocking error
+type ValidationIssue struct {
+	Description string
+	Blocking    bool
+	TimeCheck   bool
+}
+
+func (ve *ValidationIssue) Error() string {
+	return ve.Description
+}
+
+// ValidationResults is a list of ValidationIssue pointers
+type ValidationResults struct {
+	Issues []*ValidationIssue
+}
+
+// CreateValidationResults creates an empty list of validation issues
+func CreateValidationResults() *ValidationResults {
+	issues := []*ValidationIssue{}
+	return &ValidationResults{
+		Issues: issues,
+	}
+}
+
+//Add appends an issue to the list
+func (v *ValidationResults) Add(vi *ValidationIssue) {
+	v.Issues = append(v.Issues, vi)
+}
+
+// AddError creates a new validation error and adds it to the list
+func (v *ValidationResults) AddError(format string, args ...interface{}) {
+	v.Add(&ValidationIssue{
+		Description: fmt.Sprintf(format, args...),
+		Blocking:    true,
+		TimeCheck:   false,
+	})
+}
+
+// AddTimeCheck creates a new validation issue related to a time check and adds it to the list
+func (v *ValidationResults) AddTimeCheck(format string, args ...interface{}) {
+	v.Add(&ValidationIssue{
+		Description: fmt.Sprintf(format, args...),
+		Blocking:    false,
+		TimeCheck:   true,
+	})
+}
+
+// AddWarning creates a new validation warning and adds it to the list
+func (v *ValidationResults) AddWarning(format string, args ...interface{}) {
+	v.Add(&ValidationIssue{
+		Description: fmt.Sprintf(format, args...),
+		Blocking:    false,
+		TimeCheck:   false,
+	})
+}
+
+// IsBlocking returns true if the list contains a blocking error
+func (v *ValidationResults) IsBlocking(includeTimeChecks bool) bool {
+	for _, i := range v.Issues {
+		if i.Blocking {
+			return true
+		}
+
+		if includeTimeChecks && i.TimeCheck {
+			return true
+		}
+	}
+	return false
+}
+
+// IsEmpty returns true if the list is empty
+func (v *ValidationResults) IsEmpty() bool {
+	return len(v.Issues) == 0
+}
+
+// Errors returns only blocking issues as errors
+func (v *ValidationResults) Errors() []error {
+	var errs []error
+	for _, v := range v.Issues {
+		if v.Blocking {
+			errs = append(errs, errors.New(v.Description))
+		}
+	}
+	return errs
+}