Support lang="stylus" in <style> blocks

[akittas]

Many of us prefer lang="stylus" for css style blocks in SFCs, component-compiler-utils already supports that, so maybe it's easy to add?

thanks for this great plugin!

[mycarrysun]

See #79

[akittas]

@mycarrysun don't know how #79 is relevant, since rollup-plugin-vue stopped supporting lang="stylus" since version 4.x. However now it CAN be supported again using the latest version of component-compiler-utils.

[mycarrysun]

Sorry @akittas I didn't look ahead for breaking changes - I'm extracting css with postcss now and found that pr when troubleshooting a current issue with order of imports for stylesheets.