chore: 0.5.0 changelog

Author: LinusBorg

CHANGELOG.md

@@ -1,3 +1,10 @@
+# 0.5.0
+
+- New: `watchEffect` function, lingin up with the latest version of the RFC ([RFC docs](https://vue-composition-api-rfc.netlify.com/api.html#watcheffect)) (#275)
+- Fix: `setup` from a mixin should called before the componen's own (#276)
+- Fix(types): Fix corner case in `UnWrapRef` internal type (#261)
+- types: Add `Element` to bailout types for unwrapping (#278)
+
 # 0.4.0
 
 - **Refactor: rename `createComponent` to `defineComponent`** (the `createComponent` function is still there but deprecated) [#230](https://github.com/vuejs/composition-api/issues/230)