Update this library in order to get the Django2 fix in https://github.com/jazzband/django-model-utils/pull/335

We'll upgrade this again along with pytest once pytest-dev/pytest#6925 is resolved.

Also, it looks like a flaky error in test class DB setup outside a transaction was mucking things up for the rest of the test shard. I didn't try to fix the flakiness, but this should at least limit the blast radius to just that test class. We really need to start using setUpTestData() more consistently.

fixed tag issue

Upgrade uses renamed enterprise catalog endpoints

Also pinned httpretty < 1.0 because that upgrade broke many tests.

This is an unused-as-of-yet utility function to generate a bunch
of ics files for a user's course schedule. Will be used as part
of the calendar_sync feature package.

AA-37

checking django-wiki and fixing deprecation warnings.

We upgraded these before in https://github.com/edx/edx-platform/pull/23119 along with django-countries (which released a new version just before that), but had to revert in https://github.com/edx/edx-platform/pull/23237 because of a performance regression in the admin page for EnterpriseCustomer.  We think django-countries was the culprit and have pinned it, so trying these two again by themselves.

- switches to openedx-calc from PyPI
- includes edx-rest-api-client major upgrade.

ARCHBOM-952