Make it run on Python 3.8 with Django 3.0.7

[maznu]

It "runs" (but doesn't exactly "work") with this set of packages fulfilling the dependencies:

django-crispy-forms==1.9.1
django-extensions==2.2.9
  - six [required: >=1.2, installed: 1.15.0]
django-filter==2.3.0
  - Django [required: >=2.2, installed: 3.0.7]
    - asgiref [required: ~=3.2, installed: 3.2.10]
    - pytz [required: Any, installed: 2020.1]
    - sqlparse [required: >=0.2.2, installed: 0.3.1]
djangorestframework==3.11.0
  - django [required: >=1.11, installed: 3.0.7]
    - asgiref [required: ~=3.2, installed: 3.2.10]
    - pytz [required: Any, installed: 2020.1]
    - sqlparse [required: >=0.2.2, installed: 0.3.1]
requests==2.24.0
  - certifi [required: >=2017.4.17, installed: 2020.6.20]
  - chardet [required: >=3.0.2,<4, installed: 3.0.4]
  - idna [required: >=2.5,<3, installed: 2.9]
  - urllib3 [required: >=1.21.1,<1.26,!=1.25.1,!=1.25.0, installed: 1.25.9]