Update CHANGELOG.md

Author: lvukadinovic-ib

CHANGELOG.md

@@ -5,7 +5,7 @@ All notable changes to the library will be documented in this file.
 The format of the file is based on [Keep a Changelog](http://keepachangelog.com/)
 and this library adheres to [Semantic Versioning](http://semver.org/) as mentioned in [README.md][readme] file.
 
-## [ [4.0.2](https://github.com/infobip/infobip-api-csharp-client/releases/tag/v4.0.2) ] - 2025-12-08
+## [ [4.0.2](https://github.com/infobip/infobip-api-csharp-client/releases/tag/v4.0.2) ] - 2025-12-09
 
 ### Added
 - Custom Enum Converter for System.Text.Json (see ###fixed for more information).