Update CHANGELOG.md for release v0.5.0

CHANGELOG.md

@@ -5,6 +5,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+
+## [0.5.0] - 2021-09-11
 ### Added
 - `-t/--type` option for `bump` command
 
@@ -69,7 +71,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 - This Changelog and initial project files
 
-[Unreleased]: https://github.com/atwalsh/kac/compare/v0.4.1...master
+[Unreleased]: https://github.com/atwalsh/kac/compare/v0.5.0...master
+[0.5.0]: https://github.com/atwalsh/kac/compare/v0.4.1...v0.5.0
 [0.4.1]: https://github.com/atwalsh/kac/compare/v0.4.0...v0.4.1
 [0.4.0]: https://github.com/atwalsh/kac/compare/v0.3.0...v0.4.0
 [0.3.0]: https://github.com/atwalsh/kac/compare/v0.2.3...v0.3.0