update CHANGELOG for pipecat 0.0.68

Author: aconchillo

CHANGELOG.md

@@ -5,7 +5,7 @@ All notable changes to **Pipecat** will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [Unreleased]
+## [0.0.68] - 2025-05-28
 
 ### Added