use go 1.12

Signed-off-by: hongming <talonwan@yunify.com>

vendor/golang.org/x/oauth2/README.md

@@ -11,25 +11,64 @@ oauth2 package contains a client implementation for OAuth 2.0 spec.
 go get golang.org/x/oauth2
 ~~~~
 
-Or you can manually git clone the repository to
-`$(go env GOPATH)/src/golang.org/x/oauth2`.
-
 See godoc for further documentation and examples.
 
 * [godoc.org/golang.org/x/oauth2](http://godoc.org/golang.org/x/oauth2)
 * [godoc.org/golang.org/x/oauth2/google](http://godoc.org/golang.org/x/oauth2/google)
 
-## Policy for new packages
 
-We no longer accept new provider-specific packages in this repo. For
-defining provider endpoints and provider-specific OAuth2 behavior, we
-encourage you to create packages elsewhere. We'll keep the existing
-packages for compatibility.
+## App Engine
 
-## Report Issues / Send Patches
+In change 96e89be (March 2015) we removed the `oauth2.Context2` type in favor
+of the [`context.Context`](https://golang.org/x/net/context#Context) type from
+the `golang.org/x/net/context` package
 
-This repository uses Gerrit for code changes. To learn how to submit changes to
-this repository, see https://golang.org/doc/contribute.html.
+This means its no longer possible to use the "Classic App Engine"
+`appengine.Context` type with the `oauth2` package. (You're using
+Classic App Engine if you import the package `"appengine"`.)
 
-The main issue tracker for the oauth2 repository is located at
-https://github.com/golang/oauth2/issues.
+To work around this, you may use the new `"google.golang.org/appengine"`
+package. This package has almost the same API as the `"appengine"` package,
+but it can be fetched with `go get` and used on "Managed VMs" and well as
+Classic App Engine.
+
+See the [new `appengine` package's readme](https://github.com/golang/appengine#updating-a-go-app-engine-app)
+for information on updating your app.
+
+If you don't want to update your entire app to use the new App Engine packages,
+you may use both sets of packages in parallel, using only the new packages
+with the `oauth2` package.
+
+	import (
+		"golang.org/x/net/context"
+		"golang.org/x/oauth2"
+		"golang.org/x/oauth2/google"
+		newappengine "google.golang.org/appengine"
+		newurlfetch "google.golang.org/appengine/urlfetch"
+
+		"appengine"
+	)
+
+	func handler(w http.ResponseWriter, r *http.Request) {
+		var c appengine.Context = appengine.NewContext(r)
+		c.Infof("Logging a message with the old package")
+
+		var ctx context.Context = newappengine.NewContext(r)
+		client := &http.Client{
+			Transport: &oauth2.Transport{
+				Source: google.AppEngineTokenSource(ctx, "scope"),
+				Base:   &newurlfetch.Transport{Context: ctx},
+			},
+		}
+		client.Get("...")
+	}
+
+## Contributing
+
+We appreciate your help!
+
+To contribute, please read the contribution guidelines:
+	https://golang.org/doc/contribute.html
+
+Note that the Go project does not use GitHub pull requests but
+uses Gerrit for code reviews. See the contribution guide for details.