Adding release notes for 3.1.0 (#1929) (#1930)

* Adding release notes for 3.1.0



* add release notes pr



---------


(cherry picked from commit 2cb645e)

Signed-off-by: Shenoy Pratik <sgguruda@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>

Author: opensearch-trigger-bot[bot]

release-notes/opensearch-observability.release-notes-3.1.0.0.md

@@ -0,0 +1,8 @@
+## Version 3.1.0.0 Release Notes
+
+Compatible with OpenSearch 3.1.0
+
+### Maintenance
+
+- [AUTO] Increment version to 3.1.0-SNAPSHOT ([#1922](https://github.com/opensearch-project/observability/pull/1922))
+- Adding release notes for 3.1.0 ([#1929](https://github.com/opensearch-project/observability/pull/1929))