Added CHANGELOG.

Signed-off-by: dblock <[email protected]>

CHANGELOG.md

@@ -24,6 +24,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Generate `cat` client from API specs ([#529](https://github.com/opensearch-project/opensearch-py/pull/529))
 - Use API generator for all APIs ([#551](https://github.com/opensearch-project/opensearch-py/pull/551))
 - Merge `.pyi` type stubs inline ([#563](https://github.com/opensearch-project/opensearch-py/pull/563))
+- Expanded type coverage to benchmarks, samples and tests ([#566](https://github.com/opensearch-project/opensearch-py/pull/566))
 ### Deprecated
 - Deprecated point-in-time APIs (list_all_point_in_time, create_point_in_time, delete_point_in_time) and Security Client APIs (health_check and update_audit_config) ([#502](https://github.com/opensearch-project/opensearch-py/pull/502))
 ### Removed