Update vendor files to point to kubernetes-1.12.0-beta.1

vendor/golang.org/x/oauth2/yahoo/yahoo.go

@@ -0,0 +1,17 @@
+// Copyright 2017 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.
+
+// Package yahoo provides constants for using OAuth2 to access Yahoo.
+package yahoo // import "golang.org/x/oauth2/yahoo"
+
+import (
+	"golang.org/x/oauth2"
+)
+
+// Endpoint is Yahoo's OAuth 2.0 endpoint.
+// See https://developer.yahoo.com/oauth2/guide/
+var Endpoint = oauth2.Endpoint{
+	AuthURL:  "https://api.login.yahoo.com/oauth2/request_auth",
+	TokenURL: "https://api.login.yahoo.com/oauth2/get_token",
+}