chore: Update changelog for release 2.2.1

CHANGELOG.md

@@ -5,7 +5,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
-## [Unreleased]
+## [2.2.1] - 2023-03-11
 
 ### Changed
 
@@ -93,6 +93,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - Initial content including change log
 
+[2.2.1]: https://github.com/release-flow/keep-a-changelog-action/compare/v2.2.0...v2.2.1
+
 [2.2.0]: https://github.com/release-flow/keep-a-changelog-action/compare/v2.1.0...v2.2.0
 
 [2.1.0]: https://github.com/release-flow/keep-a-changelog-action/compare/v2.0.0...v2.1.0