meta: add Richard Lau to TSC list in README.md

Refs: https://github.com/nodejs/TSC/issues/1096

PR-URL: https://github.com/nodejs/node/pull/40523


Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>