Update copyright year in README.md

Author: hannesa2

README.md

@@ -99,7 +99,7 @@ dependencies {
 
 <h1 id="license">License :page_facing_up:</h1>
 
-Copyright 2025 Contributors
+© 2020 Philipp Jahoda; © 2025 AppDevNext/AndroidChart Contributors
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.