updated the 2.15 release-notes (#685) (#686)

(cherry picked from commit 889bdb8)

Signed-off-by: Riya Saxena <riysaxen@amazon.com>
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

release-notes/opensearch-common-utils.release-notes-2.15.0.0.md

@@ -5,9 +5,16 @@ Compatible with OpenSearch 2.15.0
 ### Maintenance
 * Increment version to 2.15.0-SNAPSHOT ([#651](https://github.com/opensearch-project/common-utils/pull/651))
 
+
+### Features
+* CorrelationAlert model added ([#631](https://github.com/opensearch-project/common-utils/pull/631), [#679](https://github.com/opensearch-project/common-utils/pull/679))
+
+### Bug Fixes
+* Bug fixes for correlation Alerts ([#670](https://github.com/opensearch-project/common-utils/pull/670), [#680](https://github.com/opensearch-project/common-utils/pull/680))
+
 ### Enhancements
 * Add start_time and end_time filters to GetAlertsRequest. ([#655](https://github.com/opensearch-project/common-utils/pull/655))
 * Added new models for Alerting Comments ([#663](https://github.com/opensearch-project/common-utils/pull/663), [#671](https://github.com/opensearch-project/common-utils/pull/671), [#674](https://github.com/opensearch-project/common-utils/pull/674) [#678](https://github.com/opensearch-project/common-utils/pull/678))
 
 ### Documentation
-* Added 2.15.0.0 release notes. ([#672](https://github.com/opensearch-project/common-utils/pull/672))
+* Added 2.15.0.0 release notes. ([#672](https://github.com/opensearch-project/common-utils/pull/672))