Add release notes for 1.3.18 (#14698)

Signed-off-by: Zelin Hao <zelinhao@amazon.com>

Author: zelinh

CHANGELOG.md

@@ -6,13 +6,11 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 ### Added
 ### Dependencies
-- Bump `netty` from 4.1.110.Final to 4.1.111.Final ([#14356](https://github.com/opensearch-project/OpenSearch/pull/14356))
-
 ### Changed
 ### Deprecated
 ### Removed
 ### Fixed
 
 ### Security
 
-[Unreleased 1.3.x]: https://github.com/opensearch-project/OpenSearch/compare/1.3.17...HEAD
+[Unreleased 1.3.x]: https://github.com/opensearch-project/OpenSearch/compare/1.3.18...HEAD

release-notes/opensearch.release-notes-1.3.18.md

@@ -0,0 +1,4 @@
+## 2024-07-09 Version 1.3.18 Release Notes
+
+### Upgrades
+- Bump `netty` from 4.1.110.Final to 4.1.111.Final ([#14356](https://github.com/opensearch-project/OpenSearch/pull/14356))