vendor: add github.com/diegomarangoni/gcscache

also include all transitive dependencies of gcscache, which seems to
bring in the entire world of Google Cloud Platform.

vendor/google.golang.org/api/googleapi/transport/apikey.go

@@ -0,0 +1,38 @@
+// Copyright 2012 Google Inc. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package transport contains HTTP transports used to make
+// authenticated API requests.
+package transport
+
+import (
+	"errors"
+	"net/http"
+)
+
+// APIKey is an HTTP Transport which wraps an underlying transport and
+// appends an API Key "key" parameter to the URL of outgoing requests.
+type APIKey struct {
+	// Key is the API Key to set on requests.
+	Key string
+
+	// Transport is the underlying HTTP transport.
+	// If nil, http.DefaultTransport is used.
+	Transport http.RoundTripper
+}
+
+func (t *APIKey) RoundTrip(req *http.Request) (*http.Response, error) {
+	rt := t.Transport
+	if rt == nil {
+		rt = http.DefaultTransport
+		if rt == nil {
+			return nil, errors.New("googleapi/transport: no Transport specified or available")
+		}
+	}
+	newReq := *req
+	args := newReq.URL.Query()
+	args.Set("key", t.Key)
+	newReq.URL.RawQuery = args.Encode()
+	return rt.RoundTrip(&newReq)
+}