Require nibabel >= 5.3.1 (fixes issues with enhanced DICOMs), and drop Python 3.8 support #800

yarikoptic merged 2 commits intonipy:masternipy/heudiconv:masterfrom

UNFmontreal:fix/pin_nibabel_versionUNFmontreal/heudiconv:fix/pin_nibabel_versionCopy head branch name to clipboard