Update CHANGELOG.md

Author: vitorflg

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ## [Unreleased]
 
+### Added
+-  Custom callback param to the localesChanged event.
+
 ## [8.127.0] - 2021-03-10
 
 ### Added