remove now-unused rubocop-packs dependency

[technicalpickles]

Testing this theory: #105

[technicalpickles]

This passes, so maybe a downstream use of it needs this around 🤔

[alexevanczuk]

We don't need rubocop-packs here ever since e70fde7, but I forgot to remove it then! Could you also remove the RBI and the dependency listed in the gemspec?

[technicalpickles]

@alexevanczuk done!

[mbutsko]

Any update here?

[alexevanczuk]

Thanks @technicalpickles ! If you would bump the version and merge that it'll auto release in case users want to pick it up. We're still working on my authentication to the rubyatscale repo so I can't do that yet.

[technicalpickles]

done! #113

[Dukesiver]

thanks guys