Release notes for 1.2.4.0 (#1569)

* Release notes for 1.2.4.0, cherry-picked from fce3854

Signed-off-by: Dave Lago <davelago@amazon.com>

Author: Dave Lago

release-notes/opensearch-security.release-notes-1.2.4.0.md

@@ -0,0 +1,10 @@
+## 2021-01-12 Version 1.2.4.0
+
+Compatible with OpenSearch 1.2.4
+
+### Maintenance
+
+* Bump log4j-core from 2.17.0 to 2.17.1 ([#1551](https://github.com/opensearch-project/security/pull/1551))
+* Update CXF version to 3.4.5 ([#1540](https://github.com/opensearch-project/security/pull/1540))
+* Version bump to 1.2.4.0 ([#1558](https://github.com/opensearch-project/security/pull/1558))
+* Release notes for 1.2.4.0 ([#1569](https://github.com/opensearch-project/security/pull/1569))