Replace CircleCI deployment with GHA deployment

[PGijsbers]

The CircleCI build command was outdated (pointed to master instead of main). While I would've just updated that, a few reasons to move to GHA:

• I couldn't confirm that the workflow is running as expected in the first place: after logging in to CircleCI I get into a redirect loop.
• Many other repositories in OpenML already use GHA, so there is more familiarity with the other core contributors.
• It's integrated with GH (though that's also a downside)

[PGijsbers]

@joaquinvanschoren if you are fine with this I will disable CircleCI

[joaquinvanschoren]

Yes, sounds good!