Update readme

Author: bendera

CHANGELOG.md

@@ -9,6 +9,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 ### Fixed
 
 - Fixed the `checked` state of the default selected **Radio**.
+- Fixed **RadioGroup** behavior in the shadow DOM.
 
 ## [2.3.0] - 2025-08-26