[COPYING] Update
diff --git a/COPYING b/COPYING
index 48d1b30..162945e 100644
--- a/COPYING
+++ b/COPYING
@@ -11,10 +11,12 @@
 Copyright © 2009  Keith Stribley
 Copyright © 2009  Martin Hosken and SIL International
 Copyright © 2007  Chris Wilson
-Copyright © 2005,2006,2020,2021  Behdad Esfahbod
+Copyright © 2005,2006,2020,2021,2022,2023  Behdad Esfahbod
 Copyright © 2005  David Turner
 Copyright © 2004,2007,2008,2009,2010  Red Hat, Inc.
 Copyright © 1998-2004  David Turner and Werner Lemberg
+Copyright © 2022  Matthias Clasen
+Copyright © 2018,2021  Khaled Hosny
 
 For full copyright notices consult the individual files in the package.