docs: update CHANGELOG

Author: y-young

CHANGELOG.md

@@ -11,6 +11,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Fixed
+
 - `opentelemetry-instrumentation` Fix client address is set to server address in new semconv
   ([#3354](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3354))