update CHANGELOG for 0.0.73

CHANGELOG.md

@@ -5,6 +5,14 @@ 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).
 
+## [0.0.73] - 2025-06-26
+
+### Fixed
+
+- Fixed an issue introduced in 0.0.72 that would cause `ElevenLabsTTSService`,
+  `GladiaSTTService`, `NeuphonicTTSService` and `OpenAIRealtimeBetaLLMService`
+  to throw an error.
+
 ## [0.0.72] - 2025-06-26
 
 ### Added