Fixed: #25, ReferenceError: Cache is not defined

[givingwu]

ReferenceError: Cache is not defined

(anonymous function)
internal:///Users/vuchan/Development/WorkSpace/***/node_modules/[email protected]@serviceworker-cache-polyfill/index.js:19

(function() {
> 19 |   var nativeAddAll = Cache.prototype.addAll;
  20 |   var userAgent = navigator.userAgent.match(/(Firefox|Chrome)\/(\d+\.)/);
  21 | 
  22 |   // Has nice behavior of `var` which everyone hates