Bump google.golang.org/api

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

@@ -0,0 +1,16 @@
+// Copyright 2018 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 stackoverflow provides constants for using OAuth2 to access Stack Overflow.
+package stackoverflow // import "golang.org/x/oauth2/stackoverflow"
+
+import (
+	"golang.org/x/oauth2"
+)
+
+// Endpoint is Stack Overflow's OAuth 2.0 endpoint.
+var Endpoint = oauth2.Endpoint{
+	AuthURL:  "https://stackoverflow.com/oauth",
+	TokenURL: "https://stackoverflow.com/oauth/access_token",
+}