Added release notes for OS-cross-cluster-replication_2.15.0 (#1399) (#1400)

Signed-off-by: Mohit Kumar <mohitamg@amazon.com>
(cherry picked from commit 32f28cc)

Co-authored-by: Mohit Kumar <113413713+mohitamg@users.noreply.github.com>

Author: opensearch-trigger-bot[bot]

release-notes/opensearch-cross-cluster-replication.release-notes-2.15.0.0.md

@@ -0,0 +1,6 @@
+## Version 2.15.0.0 Release Notes
+
+Compatible with OpenSearch 2.15.0
+
+### Maintenance
+* Disabling docrep to remote store migration test for integTestRemote suite ([#1379](https://github.com/opensearch-project/cross-cluster-replication/pull/1379))