Add changelog

Signed-off-by: Kunal Kotwani <kkotwani@amazon.com>

CHANGELOG.md

@@ -10,6 +10,8 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Added release notes for 2.2.1 ([#4344](https://github.com/opensearch-project/OpenSearch/pull/4344))
 - Label configuration for dependabot PRs ([#4348](https://github.com/opensearch-project/OpenSearch/pull/4348))
 - Support for HTTP/2 (server-side) ([#3847](https://github.com/opensearch-project/OpenSearch/pull/3847))
+- BWC version 2.2.2 ([#4383](https://github.com/opensearch-project/OpenSearch/pull/4383))
+
 ### Dependencies
 - Bumps `com.diffplug.spotless` from 6.9.1 to 6.10.0
 - Bumps `xmlbeans` from 5.1.0 to 5.1.1
@@ -58,4 +60,4 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 
 [Unreleased]: https://github.com/opensearch-project/OpenSearch/compare/2.2.0...HEAD
-[2.x]: https://github.com/opensearch-project/OpenSearch/compare/2.2.0...2.x
+[2.x]: https://github.com/opensearch-project/OpenSearch/compare/2.2.0...2.x