Update copyright years.

Author: HexDecimal

LICENSE.txt

@@ -1,6 +1,6 @@
 BSD 2-Clause License
 
-Copyright (c) 2009-2021, Kyle Benesch and the python-tcod contributors.
+Copyright (c) 2009-2023, Kyle Benesch and the python-tcod contributors.
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without

docs/conf.py

@@ -60,7 +60,7 @@
 
 # General information about the project.
 project = "python-tcod"
-copyright = "2009-2021, Kyle Benesch"
+copyright = "2009-2023, Kyle Benesch"
 author = "Kyle Benesch"
 
 # The version info for the project you're documenting, acts as replacement for