Adapting changelog for release

Author: sebastian-peter

CHANGELOG.md

@@ -6,6 +6,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased/Snapshot]
 
+## [0.4.0] - 2023-11-22
+
 ### Changed
 - Replacing akka with pekko [#138](https://github.com/ie3-institute/simonaAPI/issues/138)
 
@@ -28,6 +30,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Renamed messages to ease understanding [#62](https://github.com/ie3-institute/simonaAPI/issues/62)
 - Separating departures and arrivals in message protocol, properly handling exceptions [#77](https://github.com/ie3-institute/simonaAPI/issues/77)
 
-[Unreleased/Snapshot]: https://github.com/ie3-institute/simonaapi/compare/0.3.0...HEAD
+[Unreleased/Snapshot]: https://github.com/ie3-institute/simonaapi/compare/0.4.0...HEAD
+[0.4.0]: https://github.com/ie3-institute/powersystemdatamodel/compare/0.3.0...0.4.0
 [0.3.0]: https://github.com/ie3-institute/powersystemdatamodel/compare/0.2.0...0.3.0
 [0.2.0]: https://github.com/ie3-institute/powersystemdatamodel/compare/e3f0c247d9d2a92840f49412aa729c5f033cb4de...0.2.0