Use createProxy to allow use of polyfill for ie11

[oterral]

Fix #3

With this pr we can use https://github.com/GoogleChrome/proxy-polyfill .

Then you can use it like this:

// import polyfills for ie 11
import 'react-app-polyfill/ie11';
import 'react-app-polyfill/stable';
import 'abortcontroller-polyfill/dist/abortcontroller-polyfill-only';
import 'proxy-polyfill';

import { ReactWebComponent } from 'create-react-web-component';
import {
  componentAttributes,
  componentProperties,
} from './componentProperties';
import App from './App';

ReactWebComponent.setAttributes(App.attributes);
ReactWebComponent.setProperties(App.defaultProps);
ReactWebComponent.render(App, 'trafimage-maps');

[SimonHoiberg]

This is awesome man, greatly appreciated! 😄

Would you mind removing the comment above const root = ..., and then bump the patch version one?
You can just run the script yarn update-version 2.0.16, that will update the version and its references in the templates 😊

Cheers!

[oterral]

Modifications done.
And thx for this project it has really helped us.