doc: use my legal name in README

Just so that it's documented. Feel free to call me anything you want
though: Timothy, Tim, 顾天骋.

PR-URL: https://github.com/nodejs/node/pull/17894
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>

README.md

@@ -489,7 +489,7 @@ For more information about the governance of the Node.js project, see
 * [thlorenz](https://github.com/thlorenz) -
 **Thorsten Lorenz** <thlorenz@gmx.de>
 * [TimothyGu](https://github.com/TimothyGu) -
-**Timothy Gu** <timothygu99@gmail.com> (he/him)
+**Tiancheng "Timothy" Gu** <timothygu99@gmail.com> (he/him)
 * [tniessen](https://github.com/tniessen) -
 **Tobias Nießen** <tniessen@tnie.de>
 * [trevnorris](https://github.com/trevnorris) -