.mailmap: add a couple of aliases for Timothy Arceri

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/1999>
diff --git a/.mailmap b/.mailmap
index 70783fa..5b8fd66 100644
--- a/.mailmap
+++ b/.mailmap
@@ -583,6 +583,9 @@
 
 Timo Aaltonen <tjaalton@debian.org> <tjaalton@cc.hut.fi>
 
+Timothy Arceri <tarceri@itsqueeze.com> <tarceri@localhost.localdomain>
+Timothy Arceri <tarceri@itsqueeze.com> <timothy.arceri@collabora.com>
+
 Tom Fogal <tfogal@alumni.unh.edu> <tfogal@sci.utah.edu>
 
 Tom Stellard <thomas.stellard@amd.com> <tstellar@gmail.com>