doc: add MoonBall to collaborators

PR-URL: https://github.com/nodejs/node/pull/19109
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Yuta Hiroto <hello@about-hiroppy.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Jon Moss <me@jonathanmoss.me>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

README.md

@@ -429,6 +429,8 @@ For more information about the governance of the Node.js project, see
 **Julien Gilli** <jgilli@nodejs.org>
 * [mmarchini](https://github.com/mmarchini) -
 **Matheus Marchini** <matheus@sthima.com>
+* [MoonBall](https://github.com/MoonBall) -
+**Chen Gang** <gangc.cxy@foxmail.com>
 * [mscdex](https://github.com/mscdex) -
 **Brian White** <mscdex@mscdex.net>
 * [MylesBorins](https://github.com/MylesBorins) -