update changelog

Author: Conduitry

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## Unreleased
 
 * Support `<slot slot="...">` ([#2079](https://github.com/sveltejs/svelte/issues/2079))
+* Fix unmounting components with a bidirectional transition with a delay ([#4954](https://github.com/sveltejs/svelte/issues/4954))
 * Add types to `get` function in `svelte/store` ([#5269](https://github.com/sveltejs/svelte/pull/5269))
 * Add `EventSource` to known globals ([#5463](https://github.com/sveltejs/svelte/issues/5463))
 * Fix compiler exception with `~`/`+` combinators and `{...spread}` attributes ([#5465](https://github.com/sveltejs/svelte/issues/5465))