Update CHANGELOG.md

Author: tspiller

Packages/com.unity.inputsystem/CHANGELOG.md

@@ -15,6 +15,7 @@ however, it has to be formatted properly to pass verification tests.
 - Fixed arrow key navigation of Input Actions after Action rename. [ISXB-1024](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-1024)
 - Fixed gamepad navigation in UI Toolkit TextField when using InputSystemUIInputModule. [UUM-77364](https://issuetracker.unity3d.com/product/unity/issues/guid/UUM-77364)
 - Fixed issue where asset editor window splitter positions were not persisted [ISXB-1316]
+- Fixed an issue where ButtonStates are not fully updated when switching SingleUnifiedPointer. [ISXB-1356](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-1356)
 
 ### Changed
 - Changed default input action asset name from New Controls to New Actions.