fix: 添加fetch补丁

src/app.js

+import 'whatwg-fetch';
 import './public-path'
 import '!file-loader?name=[name].[ext]!./images/favicon.ico';
 import './global.less';
@@ -13,7 +14,6 @@ import 'sanitize.css/sanitize.css';
 import React from 'react';
 import ReactDOM from 'react-dom';
 import { event } from 'microser-data';
-import 'whatwg-fetch';
 import { Button, ConfigProvider, message, notification } from 'antd';
 import { ConnectedRouter } from 'connected-react-router/immutable';
 import Immutable from 'immutable';