Apply suggestion from @lmolkova

Author: lmolkova

util/opentelemetry-util-genai/CHANGELOG.md

@@ -5,7 +5,7 @@ All notable changes to this project 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).
 
-## Version 0.4b0 (2026-04-30)
+## Version 0.4b0 (2026-05-01)
 
 - Add `AgentInvocation` type with `invoke_agent` span lifecycle
   ([#4274](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4274))