Update release date

Author: Art4

CHANGELOG.md

@@ -7,7 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased](https://github.com/kbsali/php-redmine-api/compare/v2.4.0...v2.x)
 
-## [v2.4.0](https://github.com/kbsali/php-redmine-api/compare/v2.3.0...v2.4.0) - 2024-01-??
+## [v2.4.0](https://github.com/kbsali/php-redmine-api/compare/v2.3.0...v2.4.0) - 2024-01-04
 
 ### Added