CVE-2018-14732: webpack-dev-server vulnerability

This change updates to webpack-dev-server to 3.1.11

> CVE-2018-14732
>
> Severity low
> Vulnerable versions: < 3.1.11
> Patched version: 3.1.11
> An issue was discovered in lib/Server.js in webpack-dev-server before
> 3.1.11. Attackers are able to steal developer's code because the origin
> of requests is not checked by the WebSocket server, which is used for
> HMR (Hot Module Replacement). Anyone can receive the HMR message sent by
> the WebSocket server via a ws:https://127.0.0.1:8080/ connection from any
> origin.

Warning! This is based off the WS-2019-0100 branch since both change
things in package.json. That change was lower risk so I based these
changes off of it. I am having problems with some parts of the app so I
am not entirely confident these changes don't break anything. I will
work with someone to either help fix my dev environment or test on their
machine.

rails/package.json

@@ -20,7 +20,7 @@
  "devDependencies": {
  "jest": "^23.6.0",
  "react-testing-library": "^6.0.3",
- "webpack-dev-server": "2.11.2"
+ "webpack-dev-server": ">=3.1.11"
  },
  "jest": {
  "setupFiles": [