doc: update AUTHORS list

Update AUTHORS list using tools/update-authors.sh.
Update .mailmap to handle duplicates.

PR-URL: https://github.com/nodejs/node/pull/15181


Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Timothy Gu <timothygu99@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Khaidi Chu <i@2333.moe>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Roman Reiss <me@silverwind.io>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>