Adding release notes for 3.0-alpha1 (#1432)

Signed-off-by: Junwei Dai <junweid@amazon.com>
Co-authored-by: Junwei Dai <junweid@amazon.com>
(cherry picked from commit 41db8c0)
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: github-actions[bot]

CHANGELOG.md

@@ -8,20 +8,16 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.1.0/)
 ### Enhancements
 ### Bug Fixes
 ### Infrastructure
-
 ### Documentation
-
 ### Maintenance
 ### Refactoring
 
 ## [Unreleased 2.x](https://github.com/opensearch-project/anomaly-detection/compare/2.19...2.x)
 ### Features
 
-
 ### Enhancements
 - Github workflow for changelog verification ([#1413](https://github.com/opensearch-project/anomaly-detection/pull/1413))
 ### Bug Fixes
-
 ### Infrastructure
 ### Documentation
 ### Maintenance

release-notes/opensearch-anomaly-detection.release-notes-3.0.0.0-alpha1.md

@@ -0,0 +1,6 @@
+## Version 3.0.0.0-alpha1 Release Notes
+
+Compatible with OpenSearch 3.0.0.0-alpha1
+
+### Maintenance
+- Fix breaking changes for 3.0.0 release ([#1424](https://github.com/opensearch-project/anomaly-detection/pull/1424))