doc: add psmarshall to collaborators

PR-URL: #24170
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

Author: psmarshall

README.md

@@ -405,6 +405,8 @@ For information about the governance of the Node.js project, see
 **Minqi Pan** <pmq2001@gmail.com>
 * [princejwesley](https://github.com/princejwesley) -
 **Prince John Wesley** <princejohnwesley@gmail.com>
+* [psmarshall](https://github.com/psmarshall) -
+**Peter Marshall** <petermarshall@chromium.org> (he/him)
 * [Qard](https://github.com/Qard) -
 **Stephen Belanger** <admin@stephenbelanger.com> (he/him)
 * [refack](https://github.com/refack) -