Add a mailmap entry for y21

tgross35 · tgross35 · commit 240dc05371a5 · 2025-06-19T18:45:49.000-04:00
diff --git a/.mailmap b/.mailmap
@@ -698,3 +698,4 @@ Zach Pomerantz <zmp@umich.edu>
 Zack Corr <zack@z0w0.me> <zackcorr95@gmail.com>
 Zack Slayton <zack.slayton@gmail.com>
 Zbigniew Siciarz <zbigniew@siciarz.net> Zbigniew Siciarz <antyqjon@gmail.com>
+y21 <30553356+y21@users.noreply.github.com>
