doc: remove discord community

PR-URL: nodejs/node#26830
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Anto Aravinth <anto.aravinth.cse@gmail.com>
Reviewed-By: Shelley Vohr <codebytere@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>

Author: aymen94

README.md

@@ -51,7 +51,6 @@ resources:
 
 * [Questions tagged 'node.js' on StackOverflow][]
 * [#node.js channel on chat.freenode.net][]
-* [Node.js Discord Community](https://discordapp.com/invite/v7rrPdE)
 * [Node.js Slack Community](https://node-js.slack.com/)
   * To register: [nodeslackers.com](http://www.nodeslackers.com/)