CRDS check enforces wrong PEDIGREE format

[rcooper295]

The checks called in jwst_reffiles/utils/crds_checks.py enforces a PEDIGREE format (ln 28):
ValueError: ERROR, starting and ending dates in pedigree keyword must have format: mm/dd/yyyy

This is the wrong date format for CRDS reference files; the INFLIGHT pedigree dates should be hyphen-separated and have YYYY-MM-DD format rather than month-first and slash-separated (see section 1.2.5.4 of TR-MESA 2018-001). This is an issue because the dark script requires a pedigree as input and won't create the reference file unless given an (incorrect) pedigree.