更新前端静态网页获取方式，放弃使用后端获取api

frontend/node_modules/workbox-broadcast-update/index.js

@@ -0,0 +1,15 @@
+/*
+  Copyright 2018 Google LLC
+
+  Use of this source code is governed by an MIT-style
+  license that can be found in the LICENSE file or at
+  https://opensource.org/licenses/MIT.
+*/
+import { BroadcastCacheUpdate, } from './BroadcastCacheUpdate.js';
+import { BroadcastUpdatePlugin } from './BroadcastUpdatePlugin.js';
+import { responsesAreSame } from './responsesAreSame.js';
+import './_version.js';
+/**
+ * @module workbox-broadcast-update
+ */
+export { BroadcastCacheUpdate, BroadcastUpdatePlugin, responsesAreSame, };