update changelog

Author: RobinMalfait

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Stop the event from propagating in the `Popover` component ([#798](https://github.com/tailwindlabs/headlessui/pull/798))
 - Allow to click on elements inside a `Dialog.Overlay` ([#816](https://github.com/tailwindlabs/headlessui/pull/816))
 - Ensure interactability with `Popover.Panel` contents when using the `static` prop ([#857](https://github.com/tailwindlabs/headlessui/pull/857))
+- Fix initial transition in `Transition` component ([#882](https://github.com/tailwindlabs/headlessui/pull/882))
 
 ## [Unreleased - Vue]
 
@@ -20,6 +21,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Stop the event from propagating in the `Popover` component ([#798](https://github.com/tailwindlabs/headlessui/pull/798))
 - Allow to click on elements inside a `DialogOverlay` ([#816](https://github.com/tailwindlabs/headlessui/pull/816))
 - Fix SSR crash because of `useWindowEvent` ([#817](https://github.com/tailwindlabs/headlessui/pull/817))
+- Improve tree shaking ([#859](https://github.com/tailwindlabs/headlessui/pull/859))
 
 ## [@headlessui/react@v1.4.1] - 2021-08-30