Build: Add my new name to .mailmap, update it in AUTHORS.txt

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>

AUTHORS.txt

@@ -290,7 +290,7 @@ Willy Aguirre <marti1125@gmail.com>
 Romeo Zivoin <rzivoin@healthx.com>
 Shawn Miller <shawn@mediocre.com>
 kapil garg <kapilgarg1996@gmail.com>
-Michał Gołębiowski <m.goleb@gmail.com>
+Michał Gołębiowski-Owczarek <m.goleb@gmail.com>
 Brad Tippett <brad@bradtippett.com>
 Sonali-Goyal <sonaligoyal654321@gmail.com>
 Ivan Enderlin <ivan.enderlin@hoa-project.net>