Packages that have been set to private continue to appear on yarnpkg

[LucianBuzzo]

It appears that packages that have their access changed from public to private remain listed on yarnpkg.
Looking through the code, as far as I can tell, there isn't a mechanism for detecting changes in access level, which would mean the private package will remain indexed indefinitely.

[Haroenv]

Unfortunately that might be on npm's side, we are listening to changes in the registry, and visibility change doesn't seem to trigger a change event.

I'd love to have this handled automatically, possibly there's another event we can listen to? Feel free to reach out if you want to contribute