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-expiration/index.js

@@ -0,0 +1,14 @@
+/*
+  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 { CacheExpiration } from './CacheExpiration.js';
+import { ExpirationPlugin } from './ExpirationPlugin.js';
+import './_version.js';
+/**
+ * @module workbox-expiration
+ */
+export { CacheExpiration, ExpirationPlugin };