Update CHANGELOG after 2.8.4 release

Signed-off-by: Vacha Shah <vachshah@amazon.com>

CHANGELOG.md

@@ -38,7 +38,6 @@ This section is for maintaining a changelog for all breaking changes for the cli
 ## [Unreleased 2.x]
 
 ### Added
-- Add search role type for nodes in cluster stats ([#848](https://github.com/opensearch-project/opensearch-java/pull/848))
 - Add support for Hybrid query type ([#850](https://github.com/opensearch-project/opensearch-java/pull/850))
 
 ### Dependencies
@@ -51,6 +50,22 @@ This section is for maintaining a changelog for all breaking changes for the cli
 
 ### Removed
 
+### Fixed
+
+### Security
+
+## [2.8.4] - 02/20/2024
+### Added
+- Add search role type for nodes in cluster stats ([#848](https://github.com/opensearch-project/opensearch-java/pull/848))
+
+### Dependencies
+
+### Changed
+
+### Deprecated
+
+### Removed
+
 ### Fixed
 - Fix ClusterStatsResponse field deserialization ([#848](https://github.com/opensearch-project/opensearch-java/pull/848))
 
@@ -311,7 +326,8 @@ This section is for maintaining a changelog for all breaking changes for the cli
 ### Security
 
 [Unreleased 3.0]: https://github.com/opensearch-project/opensearch-java/compare/2.x...HEAD
-[Unreleased 2.x]: https://github.com/opensearch-project/opensearch-java/compare/v2.8.3...2.x
+[Unreleased 2.x]: https://github.com/opensearch-project/opensearch-java/compare/v2.8.4...2.x
+[2.8.4]: https://github.com/opensearch-project/opensearch-java/compare/v2.8.3...v2.8.4
 [2.8.3]: https://github.com/opensearch-project/opensearch-java/compare/v2.8.2...v2.8.3
 [2.8.2]: https://github.com/opensearch-project/opensearch-java/compare/v2.8.1...v2.8.2
 [2.8.1]: https://github.com/opensearch-project/opensearch-java/compare/v2.8.0...v2.8.1