Update changelog diff links

Author: Arcensoth

CHANGELOG.md

@@ -89,7 +89,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 - Implemented `status` and `faq` extensions as an exercise for developing `commanderbot-lib`
 
-[unreleased]: https://github.com/CommanderBot-Dev/commanderbot-ext/compare/v0.8.0...HEAD
+[unreleased]: https://github.com/CommanderBot-Dev/commanderbot-ext/compare/v0.9.0...HEAD
+[0.9.0]: https://github.com/CommanderBot-Dev/commanderbot-ext/compare/v0.8.0...v0.9.0
 [0.8.0]: https://github.com/CommanderBot-Dev/commanderbot-ext/compare/v0.7.0...v0.8.0
 [0.7.0]: https://github.com/CommanderBot-Dev/commanderbot-ext/compare/v0.6.0...v0.7.0
 [0.6.0]: https://github.com/CommanderBot-Dev/commanderbot-ext/compare/v0.5.0...v0.6.0