Add changes entry for implicit nullable. Closes #230

Author: oschwald

CHANGELOG.md

@@ -4,6 +4,9 @@ CHANGELOG
 3.1.0
 ------------------
 
+* This library no longer uses implicitly nullable parameter types. This
+  will fix deprecation warning in PHP 8.4. Reported by Steven Lewis.
+  GitHub #230.
 * The PHPDoc type hints have been improved for use with PHPStan.
 
 3.0.0 (2023-12-04)