Add changelog

Author: xrmx

CHANGELOG.md

@@ -11,7 +11,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Added
+
+- `opentelemetry-instrumentation-bocotore` Add support for GenAI user events
+  ([#3258](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3258))
+
 ### Fixed
+
 - `opentelemetry-instrumentation-redis` Add missing entry in doc string for `def _instrument`
   ([#3247](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3247))