Bump copyright year

Author: horgh

README.md

@@ -44,7 +44,7 @@ https://github.com/maxmind/mm-geofeed-verifier/issues
 
 # Copyright and License
 
-This software is Copyright (c) 2019 - 2025 by MaxMind, Inc.
+This software is Copyright (c) 2019 - 2026 by MaxMind, Inc.
 
 This is free software, licensed under the
 [Apache License, Version 2.0](LICENSE-APACHE) or the [MIT License](LICENSE-MIT),