Update copyright date in README

Author: flashcode

README.md

@@ -127,7 +127,7 @@ current value
 ## Copyright
 
 <!-- REUSE-IgnoreStart -->
-Copyright © 2009-2025 [Sébastien Helleu](https://github.com/flashcode)
+Copyright © 2009-2026 [Sébastien Helleu](https://github.com/flashcode)
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by