feat(workbox): upgrade workboxVersion to 4.0.0-rc.0

Author: pooya parsa

packages/workbox/lib/defaults.js

@@ -1,6 +1,6 @@
 module.exports = {
   // General
-  workboxVersion: '3.6.3-5',
+  workboxVersion: '4.0.0-rc.0',
   workboxURL: undefined,
   importScripts: [],
   autoRegister: true,