DevServer on IE: WebSocket compatibility

Created by: josias-r

Sorry to bother about IE support 😇

Describe the bug

In react-scripts 3.3.0 de webPackDevServer setup was switched from SockJS to WebSocket. see PR Since the url.format returns an URL something like ws:localhost not ws://localhost, it will throw an Syntax Error on IE.

Environment

Windows 8.1, node 10, npm 6, ie11

Steps to reproduce

1. Install create-react-app w/ react-scripts 3.3.0
2. Import react-app-polyfills (stable & ie11)
3. Set browserslist to include "IE 11" in development mode aswell
4. Run npm start
5. Open the dev server in IE

Expected behavior

The dev-server should work on IE aswell.

Actual behavior

A syntax error gets thrown.