Updated what's new

dist/preview release/what's new.md

@@ -146,6 +146,7 @@
 - Initializing gamepadManager should register the gamepad update events ([TrevorDev](https://github.com/TrevorDev))
 - Do not generate mipmaps for RawCubeTexture if OES_texture_float_linear and/or EXT_color_buffer_float extensions are not supported ([PeapBoy](https://github.com/NicolasBuecher))
 - Do not modify passed camera array parameter when creating a default pipeline ([TrevorDev](https://github.com/TrevorDev))
+- Fixed issue where VRExperienceHelper.onExitingVR observable was being fired twice ([atulyar](https://github.com/atulyar))
 
 ### Core Engine