Update vendor

vendor/github.com/google/go-containerregistry/pkg/authn/authn.go

@@ -0,0 +1,36 @@
+// Copyright 2018 Google LLC All Rights Reserved.
+//
+// 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 authn
+
+// AuthConfig contains authorization information for connecting to a Registry
+// Inlined what we use from github.com/cli/cli/config/types
+type AuthConfig struct {
+	Username string `json:"username,omitempty"`
+	Password string `json:"password,omitempty"`
+	Auth     string `json:"auth,omitempty"`
+
+	// IdentityToken is used to authenticate the user and get
+	// an access token for the registry.
+	IdentityToken string `json:"identitytoken,omitempty"`
+
+	// RegistryToken is a bearer token to be sent to a registry
+	RegistryToken string `json:"registrytoken,omitempty"`
+}
+
+// Authenticator is used to authenticate Docker transports.
+type Authenticator interface {
+	// Authorization returns the value to use in an http transport's Authorization header.
+	Authorization() (*AuthConfig, error)
+}