Update plugin to PostCSS 8 and visitors API

[RadValentin]

This PR continues the work done in #93 to make the plugin completely support PostCSS 8 as part of v2.0.0

TODO

• Find a way to check if file is ignored once per file not once per rule
• Follow PostCSS plugin guidelines closely
• Cover all possible atrules in tests
• Set "postcss": "^8.0.0" as peer and dev dependency
• Measure performance
• Consider options argument for transform function

Links

• https://evilmartians.com/chronicles/postcss-8-plugin-migration

[eshimischi]

Any progress here, some 3rd-party libraries have issues with this library not postcss 8.0 :(
for instance, vbenjs/vite-plugin-svg-icons#47

[RadValentin]

Any progress here, some 3rd-party libraries have issues with this library not postcss 8.0 :( for instance, vbenjs/vite-plugin-svg-icons#47

This PR won't fix the problem in the issue you linked, that's being caused by my plugin requiring a newer version of PostCSS (7 or 8). I can try to see if it will run on PostCSS 5 and publish an update to make the dependency less restrictive. Will take a look at it this weekend.

[RadValentin]

Any progress here, some 3rd-party libraries have issues with this library not postcss 8.0 :( for instance, vbenjs/vite-plugin-svg-icons#47

I published a new version of the prefixer, it should fix the issues you were mentioning

[windy]

any updates about this issue?

[RadValentin]

@windy I don't have time right now for this project. My estimate is that it will be done sometime in July.