Support PR reviews

[mrousavy]

Hi! Awesome action, thanks!

Have you considered also supporting PR reviews?

Instead of hiding the comment in the "Changed files" section, this also starts a review and posts it in the conversation, e.g.:

[xiongchiamiov]

One way to do this would be to hook up the linter to reviewdog; then the framework handles all the different logic for things like github reviews and all this code needs to do is run the translation layer between reviewdog and swiftlint.