Add 2.19 release notes for cross-spawn bump (#397) (#398)

Signed-off-by: Lin Wang <wonglam@amazon.com>
(cherry picked from commit 61e51bc)

Co-authored-by: Lin Wang <wonglam@amazon.com>

Author: opensearch-trigger-bot[bot]

release-notes/opensearch-ml-commons-dashboards.release-notes-2.19.0.0.md

@@ -4,4 +4,5 @@ Compatible with OpenSearch 2.19.0
 
 
 ### Maintenance
-* Increment version to 2.19.0.0 ([#387](https://github.com/opensearch-project/ml-commons-dashboards/pull/387))
+* Increment version to 2.19.0.0 ([#387](https://github.com/opensearch-project/ml-commons-dashboards/pull/387))
+* [CVE-2024-21538] Bump cross-spawn from 7.0.3 to 7.0.6 ([#385](https://github.com/opensearch-project/ml-commons-dashboards/pull/385))