Update CHANGELOG.md

Author: Steve Gilroy

CHANGELOG.md

@@ -3,7 +3,7 @@ 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).
 
-## [Unreleased]
+## [0.9.0]
 
 ### Added
 
@@ -157,7 +157,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ### Added
 - Events in Web Component indicating whether Mission Zero criteria have been met (#113)
 
-[Unreleased]: https://github.com/RaspberryPiFoundation/editor-ui/compare/v0.8.0...HEAD
+[Unreleased]: https://github.com/RaspberryPiFoundation/editor-ui/compare/v0.9.0...HEAD
 [0.1.0]: https://github.com/RaspberryPiFoundation/editor-ui/releases/tag/v0.1.0
 [0.2.0]: https://github.com/RaspberryPiFoundation/editor-ui/releases/tag/v0.2.0
 [0.3.0]: https://github.com/RaspberryPiFoundation/editor-ui/releases/tag/v0.3.0
@@ -166,4 +166,4 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 [0.6.0]: https://github.com/RaspberryPiFoundation/editor-ui/releases/tag/v0.6.0
 [0.7.0]: https://github.com/RaspberryPiFoundation/editor-ui/releases/tag/v0.7.0
 [0.8.0]: https://github.com/RaspberryPiFoundation/editor-ui/releases/tag/v0.8.0
-
+[0.9.0]: https://github.com/RaspberryPiFoundation/editor-ui/releases/tag/v0.9.0