docs: update (vueuse#4363)

Author: danielrentz

README.md

@@ -27,7 +27,6 @@ Collection of essential Vue Composition Utilities
 ## 🚀 Features
 
 - 🎪 [**Interactive docs & demos**](https://vueuse.org)
-- 🕶 **Seamless migration**: Works for **both** Vue 3 and 2
 - ⚡ **Fully tree shakeable**: Only take what you want, [bundle size](https://vueuse.org/export-size)
 - 🦾 **Type Strong**: Written in [TypeScript](https://www.typescriptlang.org/), with [TS Docs](https://github.com/microsoft/tsdoc)
 - 🔋 **SSR Friendly**