Release version 0.4.0

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]
+
+## [0.4.0] - 2021-10-07
 ### Added
 - WORKDIR command to specify the working directory within the image.
 
@@ -60,7 +62,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 - Initial release of a working version of pimod.
 
-[Unreleased]: https://github.com/Nature40/pimod/compare/v0.3.1...HEAD
+[Unreleased]: https://github.com/Nature40/pimod/compare/v0.4.0...HEAD
+[0.4.0]: https://github.com/Nature40/pimod/compare/v0.3.1...v0.4.0
 [0.3.1]: https://github.com/Nature40/pimod/compare/v0.3.0...v0.3.1
 [0.3.0]: https://github.com/Nature40/pimod/compare/v0.2.2...v0.3.0
 [0.2.2]: https://github.com/Nature40/pimod/compare/v0.2.1...v0.2.2