docs: add auto-prefix to readme

Author: streamich

README.md

@@ -9,6 +9,7 @@ __Tiny [5<sup>th</sup> generation](https://github.com/streamich/freestyler/blob/
 - __Isomorphic__ &mdash; render on server and browser, generates stable class names, and re-hydrates
 - __Performant__ &mdash; does not create wrapper components, does not use inline styles or inline `<style>` elements in the document body, but caches all class names for re-use and injects CSS using `.insertRule()` for performance
 - __`@media` queries__ and __animation `@keyframes`__ are supported
+- __Auto-prefixes__ your styles
 
 
 ## Reference