Update AUTHORS and DONORS list

New contributor added to AUTHORS:
@kleonc

Thanks to all contributors and donors for making Godot possible!

(cherry picked from commit 44ab5a0)

.mailmap

@@ -68,6 +68,7 @@ Kanabenki <[email protected]> <[email protected]
 Kelly Thomas <[email protected]>
 Kongfa Waroros <[email protected]>
 K. S. Ernest (iFire) Lee <[email protected]>
+kleonc <[email protected]> <[email protected]>
 Leon Krause <[email protected]> <[email protected]>
 Leon Krause <[email protected]> <[email protected]>
 Liz Haas <[email protected]>
@@ -94,6 +95,7 @@ Nathan Warden <[email protected]> <[email protected]>
 Nils ANDRÉ-CHANG <[email protected]>
 Nils ANDRÉ-CHANG <[email protected]> <[email protected]>
 Nuno Donato <[email protected]> <[email protected]>
+Pawel Kowal <[email protected]>
 Pedro J. Estébanez <[email protected]> <[email protected]>
 Paul Batty <[email protected]>
 Paul Batty <[email protected]> <[email protected]>

AUTHORS.md

@@ -109,6 +109,7 @@ name is available.
     Julian Murgia (StraToN)
     Justo Delgado (mrcdk)
     Kelly Thomas (KellyThomas)
+    kleonc
     Kongfa Waroros (gongpha)
     Kostadin Damyanov (Max-Might)
     K. S. Ernest (iFire) Lee (fire)