Fix Foundation changelog

Author: madsmtm

objc2/CHANGELOG_FOUNDATION.md

@@ -8,6 +8,14 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## Unreleased - YYYY-MM-DD
 
+### Added
+* Added `NSSet`.
+* Added `NSMutableSet`.
+* Added `NSMutableDictionary`.
+
+
+## objc2 0.3.0-beta.2 - 2022-08-28
+
 ### Added
 * Added `NSNumber`.
 * Added `NSError`.