Build: Add my new name to .mailmap

Author: mgol

.mailmap

@@ -49,6 +49,7 @@ Markandey Singh <mark.dawn@gmail.com> <markande@whilebattle-lm.(none)>
 Matthew David Litwin <mlitwin@kcptech.com>
 Maurice Gottlieb <magoo@maugo.de>
 Max Rabin <rabin.max@gmail.com>
+Michał Gołębiowski-Owczarek <m.goleb@gmail.com>
 Oliver Frietsch <oliver.frietsch@web.de>
 Patty Toland <patty@filamentgroup.com>
 Peter Körner <github@mazdermind.de>