Upgrade to Stylis 4

[ricokahler]

thysultan has recently dropped stylis 4 which has a bunch of new feature including the ability to get to the AST of the stylis language.

This is kind of awesome because this lib can use that AST to do more direct and less buggy transformations for SSR mode (bye bye regex lol).

As an added bonus, stylis 4 has a significantly smaller bundle which would make the standalone bundle go down to about ~5kB. That would make us smaller than JSS and emotion!