Update CHANGELOG.md

Author: baseballyama

CHANGELOG.md

@@ -1,14 +1,15 @@
 # Svelte changelog
 
-## 3.55.1 (unreleased)
+## Unreleased
 
-* add missing `submitter` property to `on:submit` event type
+* Add missing `submitter` property to `on:submit` event type
 * Fix static `<svelte:element>` optimization in production mode ([#7938](https://github.com/sveltejs/svelte/pull/7938))
 * Fix `draw` transition with delay showing a dot at the beginning of transition ([#6816](https://github.com/sveltejs/svelte/issues/6816))
 * Fix `svelte-ignore` comment breaks named slot ([#8075](https://github.com/sveltejs/svelte/issues/8075))
 * Fix duplicate event listeners for `<svelte:element on:event>` ([#8129](https://github.com/sveltejs/svelte/issues/8129))
 * Fix max call stack exceeded ([#7032](https://github.com/sveltejs/svelte/issues/7032))
 * Revert to prevent running init binding unnecessarily ([#8103](https://github.com/sveltejs/svelte/issues/8103))
+* Improve `is_promise` logic ([#8162](https://github.com/sveltejs/svelte/pull/8162))
 
 ## 3.55.0