.mailmap: add a few aliases for Karol Herbst

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/1999>
diff --git a/.mailmap b/.mailmap
index 7da6b9f..348bf88 100644
--- a/.mailmap
+++ b/.mailmap
@@ -334,6 +334,10 @@
 Karl Schultz <karl.w.schultz@gmail.com> <Karl.W.Schultz@gmail.com>
 Karl Schultz <karl.w.schultz@gmail.com> <kschultz@freedesktop.org>
 
+Karol Herbst <kherbst@redhat.com> <git@karolherbst.de>
+Karol Herbst <kherbst@redhat.com> <karolherbst@gmail.com>
+Karol Herbst <kherbst@redhat.com> <nouveau@karolherbst.de>
+
 Keith Harrison <sio2@users.sourceforge.net> sio2 <sio2>
 
 Keith Packard <keithp@keithp.com> <keithp@koto.keithp.com>