CI skips docker build/push if tag is on commit with "DOC: " message

[effigies]

Forgot to update the release date for 20.2.5, did it with a DOC: message, and the workflow powered through: https://app.circleci.com/pipelines/github/nipreps/fmriprep/506/workflows/e70958be-c88e-46c0-b48f-91eb77753401

We should probably skip those checks for tags.

The code is already on PyPI, so we should build locally and push. @oesteban who all has credentials to do the push? Happy to let you build if that's easiest. Or I can push to markiewicz/fmriprep:20.2.5 and you can re-tag?

[oesteban]

I can build and push.

[effigies]

I'll submit a PR for the CircleCI config.

[oesteban]

Pushing ATM. Should be up within minutes.