[skip ci] update CHANGELOG

Author: jcheron

CHANGELOG.md

@@ -5,7 +5,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 ## [Unrelease]
 - Nothing
-## [2.4.0] 
+## [2.4.0] 2020-12-31
 ### Added
 - PHP8 attributes support => with PHP8, Ubiquity uses the PHP8 attributes system for annotations. 
 - `password_verify` method to `URequest`