Add 2.12 release notes (#851) (#854)

* Add 2.12 release notes



* Add another PR to release notes



---------


(cherry picked from commit 74de907)

Signed-off-by: Chase Engelbrecht <engechas@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>

release-notes/opensearch-notifications.release-notes-2.12.0.0.md

@@ -0,0 +1,24 @@
+## Version 2.12.0.0 2024-02-06
+
+Compatible with OpenSearch 2.12.0
+
+### Maintenance
+* Increment version to 2.12.0-SNAPSHOT ([#780](https://github.com/opensearch-project/notifications/pull/780))
+* Update dependency org.json:json to v20231013 ([#795](https://github.com/opensearch-project/notifications/pull/795))
+* Replace the TestMailServer to GreenMail server ([#807](https://github.com/opensearch-project/notifications/pull/807))
+* Re-enable detekt ([#796](https://github.com/opensearch-project/notifications/pull/796))
+* Removed default admin credentials. ([#837](https://github.com/opensearch-project/notifications/pull/837))
+* Force logback to use 1.3.14 ([#849](https://github.com/opensearch-project/notifications/pull/849))
+* Bump ktlint version to fix CVE ([#850](https://github.com/opensearch-project/notifications/pull/850))
+
+### Enhancements
+* Improve security plugin enabling check ([#792](https://github.com/opensearch-project/notifications/pull/792))
+
+### Infrastructure
+* Fix integration test failure by allowing direct access to system index warning ([#784](https://github.com/opensearch-project/notifications/pull/784))
+* Add github workflow to auto bump bwc version ([#799](https://github.com/opensearch-project/notifications/pull/799))
+* Onboard prod jenkins docker image to github actions ([#809](https://github.com/opensearch-project/notifications/pull/809))
+* Update Gradle to 8.5 ([#824](https://github.com/opensearch-project/notifications/pull/824))
+
+### Documentation
+* Add 2.12.0 release notes ([#851](https://github.com/opensearch-project/notifications/issues/851))