Add 2.9 release notes (#952)

Signed-off-by: Tyler Ohlsen <[email protected]>
(cherry picked from commit c7c6a46)

release-notes/opensearch-anomaly-detection.release-notes-2.9.0.0.md

@@ -0,0 +1,16 @@
+Compatible with OpenSearch 2.9.0.
+
+### Enhancements
+
+* Enforce DOCUMENT Replication for AD Indices and Adjust Primary Shards ([#948](https://github.com/opensearch-project/anomaly-detection/pull/948))
+
+### Infrastructure
+
+* Updated Maintainers and CODE_OWNERS list ([#926](https://github.com/opensearch-project/anomaly-detection/pull/926))
+* Bump guava version to 32.0.1 ([#933](https://github.com/opensearch-project/anomaly-detection/pull/933))
+* Bump scipy from 1.8.0 to 1.10.0 in /dataGeneration ([#943](https://github.com/opensearch-project/anomaly-detection/pull/943))
+* Fix main build - update import of Releasable and remove reference to BaseExceptionsHelper ([#930](https://github.com/opensearch-project/anomaly-detection/pull/930))
+
+### Documentation
+
+* Updated Maintainers and CODE_OWNERS list ([#926](https://github.com/opensearch-project/anomaly-detection/pull/926))