Unpinned a number of requirements so they would be upgraded as part of`make upgrade` as recommended by OEP-18. In particular the edx-enterprise-datadjango app was not pinning edx-drf-extensions which resulted in 2 differentversions of DRF in the requirements (one for enterprise-data and one for thisIDA).Upgrading DRF resulting in an assertion failure that was added in DRF 3.7.4```Cannot both declare the field 'created' and include it in the CourseProgramMetadataSerializer'exclude' option. Remove the field or, if inherited from a parent serializer, disable with `created = None`.```encode/django-rest-framework#5599Because the created date was being excluded, it is not needed in the CourseProgramMetadataSerializer andhas been removed.

* Test current behavior of exclude+declared field* Assert declared fields are not present in exclude