update changelog

Author: RobinMalfait

CHANGELOG.md

@@ -35,6 +35,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixes
 
 - Fix incorrect `DOM` node from ref ([#249](https://github.com/tailwindlabs/headlessui/pull/249))
+- Fix broken behaviour since Vue 3.0.5 ([#279](https://github.com/tailwindlabs/headlessui/pull/279))
 
 ### Added