dokku_packages_state doesn't support version pinning

[strugee]

Description of problem

dokku_version and friends are marked deprecated in favor of dokku_packages_state, but the latter doesn't support pinning the Dokku version. I'm uncomfortable simply specifying latest in a world where Dokku still routinely ships breaking changes.

Seems like this should take either the current values or a version number? I might also be misunderstanding the impetus for this deprecation - I'm guessing it's to avoid specifying conflicting *_version numbers, but I could be wrong.

Omitting the rest of the issue template since it obviously isn't relevant.