chore: Update changelog for version 6.6.22 (#795)

- Add version 6.6.22 entry to debian/changelog

Author: dengzhongyuan365-dev

debian/changelog

@@ -1,3 +1,9 @@
+deepin-screen-recorder (6.6.22) unstable; urgency=medium
+
+  * fix: Refine background rendering logic for toolbar in recording modes
+
+ -- dengzhongyuan <[email protected]>  Fri, 23 Jan 2026 14:17:18 +0800
+
 deepin-screen-recorder (6.6.21) unstable; urgency=medium
 
   * fix(mainwindow): Enhance mouse position checks for toolbar visibility