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-webpack-plugin/src/index.ts

@@ -0,0 +1,19 @@
+/*
+  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 {GenerateSW, GenerateSWConfig} from './generate-sw';
+import {InjectManifest} from './inject-manifest';
+
+/**
+ * @module workbox-webpack-plugin
+ */
+export {GenerateSW, GenerateSWConfig, InjectManifest};
+
+// TODO: remove this in v7.
+// See https://github.com/GoogleChrome/workbox/issues/3033
+export default {GenerateSW, InjectManifest};