add change log

Author: eruvanos

CHANGELOG.md

@@ -8,6 +8,7 @@ Arcade [PyPi Release History](https://pypi.org/project/arcade/#history) page.
 - GUI
   - Fix a bug, where the caret of UIInputText was misplaced after resizing the widget
   - Use incremental layout for UIScrollArea to improve performance of changing text
+  - Refactored and improved focus handling
 
 ## 3.3.2