Update copyright year

Author: oschwald

README.md

@@ -286,6 +286,6 @@ This API uses [Semantic Versioning](https://semver.org/).
 
 ## Copyright and License ##
 
-This software is Copyright (c) 2015-2021 by MaxMind, Inc.
+This software is Copyright (c) 2015-2022 by MaxMind, Inc.
 
 This is free software, licensed under the Apache License, Version 2.0.