Added Release Notes for v3.1.0 (#1428)

Signed-off-by: Vaibhav Agarwal <[email protected]>

Author: vaibhoag

release-notes/opensearch-index-management.release-notes-3.1.0.0.md

@@ -0,0 +1,10 @@
+## Version 3.1.0.0 2025-06-16
+
+Compatible with OpenSearch 3.1.0
+
+### Bug Fixes
+* Removed unnecessary user notifications for version conflict exceptions in Snapshot Management ([#1413](https://github.com/opensearch-project/index-management/pull/1413))
+
+
+### Maintenance
+* [AUTO] Increment version to 3.1.0-SNAPSHOT ([#1414](https://github.com/opensearch-project/index-management/pull/1414))