[Backport 2.x] Update v2.12.0 Release Notes (#984)

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

release-notes/opensearch-index-management-dashboards-plugin.release-notes-2.12.0.0.md

@@ -7,6 +7,7 @@ Compatible with OpenSearch-Dashboards 2.12.0
 * Remove unused integtest.sh file ([#954](https://github.com/opensearch-project/index-management-dashboards-plugin/pull/954))
 * Increment version to 2.12.0.0 ([#928](https://github.com/opensearch-project/index-management-dashboards-plugin/pull/928))
 * Update the babel require ([#935](https://github.com/opensearch-project/index-management-dashboards-plugin/pull/935))
+* Update browserify-sign to fix cve-2023-46234 ([#978](https://github.com/opensearch-project/index-management-dashboards-plugin/pull/978))
 
 ### Enhancements