[ENH] sanitize entities in rename spec

[Remi-Gau]

• closes [ENH]: file.rename could change . to pt in the case of spec.entities.xxx = num2str(1.5) #671

[Remi-Gau]

input_filename = 'wuasub-01_task-faceRecognition_bold.nii';

file = bids.File(input_filename, 'use_schema', false);

spec.prefix = '';
spec.entities.desc = 'bold';
spec.entities.res = '1.5';
spec.entities.label = 'GM';
spec.suffix = 'dseg';
spec.ext = '.json';
spec.entity_order = {'sub', 'task', 'label', 'res', 'desc'};

file = file.rename('spec', spec);
file.filename

ans =
    'sub-01_task-faceRecognition_label-GM_res-1pt5_desc-bold_dseg.json'

[marcobarilari]

Thank you!