add changelog

Signed-off-by: Jakob Hahn <jakob.hahn@hetzner.com>

CHANGELOG.md

@@ -17,13 +17,16 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Moved Error structs from opensearchapi to opensearch package ([#512](https://github.com/opensearch-project/opensearch-go/pull/506))
 - Move parseError function from opensearchapi to opensearch package as ParseError ([#512](https://github.com/opensearch-project/opensearch-go/pull/506))
 - Change ParseError function to do type assertion to determine error type ([#512](https://github.com/opensearch-project/opensearch-go/pull/506))
+- Removed unused structs and functions from opensearch ([#517](https://github.com/opensearch-project/opensearch-go/pull/517))
+- Adjust and extent opensearch tests for better coverage ([#517](https://github.com/opensearch-project/opensearch-go/pull/517))
 
 ### Deprecated
 
 ### Removed
 
 ### Fixed
 - Fix search request missing a slash when no indices are given ([#470](https://github.com/opensearch-project/opensearch-go/pull/469))
+- Fix opensearchtransport check for nil response body ([#517](https://github.com/opensearch-project/opensearch-go/pull/517))
 
 ### Security
 
@@ -185,4 +188,4 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 [2.1.0]: https://github.com/opensearch-project/opensearch-go/compare/v2.0.1...v2.1.0
 [2.0.1]: https://github.com/opensearch-project/opensearch-go/compare/v2.0.0...v2.0.1
 [2.0.0]: https://github.com/opensearch-project/opensearch-go/compare/v1.1.0...v2.0.0
-[1.0.0]: https://github.com/opensearch-project/opensearch-go/compare/v1.0.0...v1.1.0
+[1.0.0]: https://github.com/opensearch-project/opensearch-go/compare/v1.0.0...v1.1.0