update what's new

dist/preview release/what's new.md

@@ -15,6 +15,7 @@
 - Refactor of the SolidParticleSystem code for performance and code quality improvement ([barroij](https://github.com/barroij))
 - Added utility function `Tools.BuildArray` for array initialisation ([barroij](https://github.com/barroij))
 - Introduced a new `IOfflineSupport` interface to hide IndexedDB ([Deltakosh](https://github.com/deltakosh))
+- Performance oriented change (prevent avoidable matrix inversion or square root computation) ([barroij](https://github.com/barroij))
 
 ### glTF Loader