Add changelog

Author: xrmx

CHANGELOG.md

@@ -45,6 +45,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#3161](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3161))
 - `opentelemetry-opentelemetry-botocore` Add basic support for GenAI attributes for AWS Bedrock InvokeModel API
   ([#3200](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3200))
+- `opentelemetry-opentelemetry-botocore` Add basic support for GenAI attributes for AWS Bedrock ConverseStream API
+  ([#3204](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3204))
 
 ### Fixed