Django 2.1 no longer supported by django-ucamlookup

django-2.1-python-3.7-alpine build fails with:

The conflict is caused by:
    The user requested django<2.2 and >=2.1.5
    django-automationcommon 1.21 depends on django
    django-automationoauth 0.0.0 depends on django<2.2 and >=1.8
    django-ucamlookup 3.0.5 depends on django>=2.2

Probably time to drop django 2.1 builds.