.mailmap: add an alias for Chad Versace

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/1999>
diff --git a/.mailmap b/.mailmap
index 94825b4..39cbf2a 100644
--- a/.mailmap
+++ b/.mailmap
@@ -112,6 +112,7 @@
 Chad Versace <chadversary@chromium.org> <Chad Versace chad@chad-versace.us>
 Chad Versace <chadversary@chromium.org> <chad.versace@intel.com>
 Chad Versace <chadversary@chromium.org> <chad.versace@linux.intel.com>
+Chad Versace <chadversary@chromium.org> <chadversary@google.com>
 
 Chia-I Wu <olvaffe@gmail.com> <olv@lunarg.com>
 Chia-I Wu <olvaffe@gmail.com> Chia-Wu <olvaffe@gmail.com>