doc: add mafintosh to collaborators

PR-URL: #19773
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>

Author: mafintosh

README.md

@@ -252,6 +252,8 @@ For more information about the governance of the Node.js project, see
 **James M Snell** <jasnell@gmail.com> (he/him)
 * [joyeecheung](https://github.com/joyeecheung) -
 **Joyee Cheung** <joyeec9h3@gmail.com> (she/her)
+* [mafintosh](https://github.com/mafintosh)
+**Mathias Buus** <mathiasbuus@gmail.com> (he/him)
 * [mcollina](https://github.com/mcollina) -
 **Matteo Collina** <matteo.collina@gmail.com> (he/him)
 * [mhdawson](https://github.com/mhdawson) -