(enh) directly define class label metadata [skip-ci]
(enh) directly define class label metadata [skip-ci]

poldracklab/fmriprep,oesteban/fmriprep,oesteban/fmriprep,poldracklab/preprocessing-workflow,poldracklab/fmriprep,oesteban/fmriprep,poldracklab/fmriprep,poldracklab/preprocessing-workflow