meta: add mailmap entry for abmusse

PR-URL: #55182
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

.mailmap

@@ -2,6 +2,7 @@
 Aaron Bieber <aaron@bolddaemon.com> <deftly@gmail.com>
 Aaron Heckmann <aaron.heckmann@gmail.com> <aaron.heckmann+github@gmail.com>
 Aayush Ahuja <aayush.a@directi.com>
+Abdirahim Musse <abdirahim.musse@ibm.com> <33973272+abmusse@users.noreply.github.com>
 Abe Fettig <abefettig@gmail.com> <abe@fettig.net>
 Abhimanyu Vashisht <abhimanyuvashisht.av@gmail.com>
 Adam Langley <agl@imperialviolet.org> <agl@google.com>