Updating version in changelog.

com.unity.perception/CHANGELOG.md

 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
-## [0.3.0-preview.1] - 2020-08-07
+## [0.3.0-preview.2] - 2020-08-07
 
 ### Added