Update changelog for version 0.9.0

changelog.md

@@ -4,6 +4,11 @@ All notable changes to this project will be documented in this file.
 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) (after version 0.0.5).
 
+## [0.9.0] - 2023-08-06
+### Changed
+- Sort constraints ([Issue #44](https://github.com/KarnerTh/mermerd/issues/44))
+- Add NOT NULL constraint to description ([Issue #42](https://github.com/KarnerTh/mermerd/issues/42)
+
 ## [0.8.1] - 2023-07-14
 ### Fixed
 - Sort column names ([Issue #40](https://github.com/KarnerTh/mermerd/issues/40))
@@ -134,6 +139,8 @@ by `--showDescriptions enumValues` (for details see [PR #32](https://github.com/
 ### Added
 - Initial release of mermerd
 
+[0.9.0]: https://github.com/KarnerTh/mermerd/releases/tag/v0.9.0
+
 [0.8.1]: https://github.com/KarnerTh/mermerd/releases/tag/v0.8.1
 
 [0.8.0]: https://github.com/KarnerTh/mermerd/releases/tag/v0.8.0