add changelog

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

Author: luyuncheng

CHANGELOG.md

@@ -50,6 +50,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Change http code for DecommissioningFailedException from 500 to 400 ([#5283](https://github.com/opensearch-project/OpenSearch/pull/5283))
 - Improve summary error message for invalid setting updates ([#4792](https://github.com/opensearch-project/OpenSearch/pull/4792))
 - Replace the deprecated IndexReader APIs with new storedFields() & termVectors() ([#7792](https://github.com/opensearch-project/OpenSearch/pull/7792))
+
 ### Deprecated
 
 ### Removed