Update CHANGELOG

Author: BenGraterUnity

com.unity.postprocessing/CHANGELOG.md

@@ -4,13 +4,13 @@ All notable changes to this package will be documented in this file.
 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).
 
-## [Unreleased]
+## [3.5.0] - 2025-06-12
 
 ### Added
 - Added Switch2 platform support
 
 ### Fixed
-- 
+- Documentation updates
 
 ## [3.4.0] - 2023-12-11