Update AUTHORS and DONORS list

New contributor added to AUTHORS:
@muiroc

Thanks to all contributors and donors for making Godot possible!

Sorry for the late March update and missed February update, I made sure
to include patrons for both February and March in this commit.

Author: akien-mga

.mailmap

@@ -24,7 +24,9 @@ Chris Bradfield <chris@kidscancode.org> <cb@scribe.net>
 Clay John <claynjohn@gmail.com>
 Clay John <claynjohn@gmail.com> <clayjohn@shaw.ca>
 Dana Olson <dana@shineuponthee.com> <adolson@gmail.com>
+dankan1890 <mewuidev2@gmail.com>
 Daniel J. Ramirez <djrmuv@gmail.com>
+Emmanuel Barroga <emmanuelbarroga@gmail.com>
 Erik Selecký <35656626+rxlecky@users.noreply.github.com>
 Erik Selecký <35656626+rxlecky@users.noreply.github.com> <35656626+SeleckyErik@users.noreply.github.com>
 Fabian <supagu@gmail.com>

AUTHORS.md

@@ -124,6 +124,7 @@ name is available.
     Michael Alexsander (YeldhamDev)
     MichiRecRoom (LikeLakers2)
     mrezai
+    muiroc
     Nathan Warden (NathanWarden)
     Nils André-Chang (NilsIrl)
     Nuno Donato (nunodonato)