Updating what's new

dist/preview release/what's new.md

@@ -52,6 +52,7 @@
 
 - VR experience helper will now fire pointer events even when no mesh is currently hit ([TrevorDev](https://github.com/TrevorDev))
 - RawTexture.CreateAlphaTexture no longer fails to create a usable texture ([TrevorDev](https://github.com/TrevorDev))
+- SceneSerializer.SerializeMesh now serializes all materials kinds (not only StandardMaterial) ([julien-moreau](https://github.com/julien-moreau))
 
 ### Core Engine