chore: update golang version

vendor/google.golang.org/api/option/credentials_notgo19.go

@@ -0,0 +1,22 @@
+// Copyright 2018 Google LLC.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !go1.9
+
+package option
+
+import (
+	"golang.org/x/oauth2/google"
+	"google.golang.org/api/internal"
+)
+
+type withCreds google.DefaultCredentials
+
+func (w *withCreds) Apply(o *internal.DialSettings) {
+	o.Credentials = (*google.DefaultCredentials)(w)
+}
+
+func WithCredentials(creds *google.DefaultCredentials) ClientOption {
+	return (*withCreds)(creds)
+}