Update CHANGELOG-v3.89.md

Author: photonstorm

changelog/3.89/CHANGELOG-v3.89.md

@@ -2,6 +2,10 @@
 
 ## New Features
 
+* `GameObjects.Rectangle.setRounded` is a new method that will allow the Rectangle Shape Game Object to have rounded corners. Pass the radius to set for the corners, or pass a value of zero to disable rounded corners.
+* `GameObjects.Rectangle.isRounded` is a new read-only boolean that can be used to determine if the Rectangle Shape Game Object has rounded corners, or not.
+* `GameObjects.Rectangle.radius` is a new read-only number that is the size of the rounded corners. Do not set directly, instead use the method `setRounded`.
+
 ## Updates
 
 * The `EXPAND` Scale Mode has been updated to now clamp the size of the canvas that is created, preventing it from growing too large on landscape ultra-wide displays. Fix #7027 (thanks @leha-games @rexrainbow)