Updates CHANGELOG

CHANGELOG.md

@@ -15,6 +15,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/) and this p
 ### Fixed
 
 - Fixes [#2533](https://github.com/gitkraken/vscode-gitlens/issues/2533) - Current Branch Only graph filter sometimes fails
+- Fixes [#2504](https://github.com/gitkraken/vscode-gitlens/issues/2504) - Graph header theme colors were referencing the titlebar color properties
 
 ## [13.3.1] - 2023-02-24