Edited what's new for preview release

dist/preview release/what's new.md

@@ -14,6 +14,7 @@
 
 - Simplified code contributions by fully automating the dev setup with gitpod ([nisarhassan12](https://github.com/nisarhassan12))
 - Add a `CascadedShadowMap.IsSupported` method and log an error instead of throwing an exception when CSM is not supported ([Popov72](https://github.com/Popov72))
+- Added initial code for DeviceInputSystem ([PolygonalSun](https://github.com/PolygonalSun))
 
 ### Engine