Update what's new

dist/preview release/what's new.md

@@ -148,6 +148,7 @@
 - Added support for animations import from separate files ([noalak](https://github.com/noalak/))
 - Use web workers to validate glTF to avoid blocking the main thread. ([bghgary](https://github.com/bghgary))
 - Update glTF validator to 2.0.0-dev.3.1. ([bghgary](https://github.com/bghgary))
+- Fix an issue with disposing materials and textures too aggressively in MSFT_lod loader extension. ([bghgary](https://github.com/bghgary))
 
 ### Materials