Major Python dependency updates

[robhudson]

• Fix github tests by passing headers positional arg
• Downgrade greenlet to satisfy meinheld requirements
• Downgrade pyflakes to satisfy flake8 dependency requirements
• Remove unused ipaddress dependency
• Bump meinheld from 1.0.1 to 1.0.2, plus dependencies
• Remove unused configparser dependency
• Bump netaddr from 0.7.19 to 0.8.0
• Remove unused enum34 dependency
• Bump pyflakes from 2.1.1 to 2.4.0
• Add typing-extensions 3.10.0.2 as a new dependency of importlib-metadata
• Add PyNaCl 1.4.0 as a new dependency of PyGithub
• Add charset-normalizer 2.0.6 as a new dependency of requests
• Remove unused wcwidth dependency
• Bump urlwait from 0.4 to 1.0
• Bump redis from 3.4.1 to 3.5.3
• Bump pyparsing from 2.4.6. to 2.4.7
• Bump importlib-metadata from 1.5.0 to 4.8.1
• Bump PyGithub from 1.46 to 1.55, including dependencies
• Bump josepy from 1.2.0 to 1.10.0, plus dependencies
• Bump wrapt from 1.12.1 to 1.13.1
• Bump zipp from 3.1.0 to 3.6.0
• Bump djangorestframework from 3.11.0 to 3.12.4
• Bump django-watchman from 0.17.0 to 1.2.0
• Bump django-extensions from 2.2.8 to 3.1.3
• Bump django-csp from 3.5 to 3.7
• Bump django-crum from 0.7.5 to 0.7.9
• Bump django-cache-url from 3.0.0 to 3.2.3
• Bump attrs from 19.3.0 to 21.2.0
• Bump pycodestyle from 2.5.0 to 2.7.0
• Bump gunicorn from 19.9.0 to 20.1.0 (from PR Bump gunicorn from 19.9.0 to 20.1.0 #408)
• Bump pbr from 5.4.4 to 5.6.0 (from PR Bump pbr from 5.4.4 to 5.6.0 #423)
• Bump spinach from 0.0.11 to 0.0.14 (from PR Bump spinach from 0.0.11 to 0.0.14 #428)
• Bump flake8 from 3.7.9 to 3.9.2 (from PR Bump flake8 from 3.7.9 to 3.9.2 #429)
• Bump typing from 3.7.4 to 3.7.4.3 (from PR Bump typing from 3.7.4 to 3.7.4.3 #246)
• Bump six from 1.12.0 to 1.16.0
• Bump contextlib2 from 0.5.5 to 21.6.0 (from PR Bump contextlib2 from 0.5.5 to 21.6.0 #455)
• Bump py from 1.8.1 to 1.10.0 (from PR [Security] Bump py from 1.8.1 to 1.10.0 #352)
• Downgrade psycopg2-binary
• Upgrade to latest Django 2.2.x
• Bump Jinja2 and dep after django-jinja update
• Add toml and iniconfig for updated pytest
• Bump python-decouple from 3.1 to 3.5 (from PR Bump python-decouple from 3.1 to 3.5 #499)
• Bump pytz from 2019.3 to 2021.3 (from PR Bump pytz from 2019.3 to 2021.3 #498)
• Bump django-filter from 2.2.0 to 21.1 (from PR Bump django-filter from 2.2.0 to 21.1 #490)
• Bump more-itertools from 8.2.0 to 8.10.0 (from PR Bump more-itertools from 8.2.0 to 8.10.0 #489)
• Bump sqlparse from 0.3.0 to 0.4.2 (from PR Bump sqlparse from 0.3.0 to 0.4.2 #487)
• Bump django-jinja from 2.4.1 to 2.9.1 (from PR Bump django-jinja from 2.4.1 to 2.9.1 #485)
• Bump pillow from 8.0.1 to 8.3.2 (from PR Bump pillow from 8.0.1 to 8.3.2 #484)
• Bump deprecated from 1.2.7 to 1.2.13 (from PR Bump deprecated from 1.2.7 to 1.2.13 #482)
• Bump pluggy from 0.13.1 to 1.0.0 (from PR Bump pluggy from 0.13.1 to 1.0.0 #477)
• Bump django-pagedown from 2.1.3 to 2.2.1 (from PR Bump django-pagedown from 2.1.3 to 2.2.1 #473)
• Bump mozilla-django-oidc from 1.2.2 to 2.0.0 (from PR Bump mozilla-django-oidc from 1.2.2 to 2.0.0 #470)
• Bump whitenoise from 5.0.1 to 5.3.0 (from PR Bump whitenoise from 5.0.1 to 5.3.0 #467)
• Bump cffi from 1.12.3 to 1.14.6 (from PR Bump cffi from 1.12.3 to 1.14.6 #466)
• Bump packaging from 20.1 to 21.0 (from PR Bump packaging from 20.1 to 21.0 #458)
• Bump pytest from 5.4.1 to 6.2.5 (from PR Bump pytest from 5.4.1 to 6.2.5 #479)
• Bump psycopg2-binary from 2.8.3 to 2.9.1 (from PR Bump psycopg2-binary from 2.8.3 to 2.9.1 #453)
• Bump pytest-django from 3.8.0 to 4.4.0 (from PR Bump pytest-django from 3.8.0 to 4.4.0 #449)

[pmac]

Everything is working well for me locally. I just had to change the version of Postgres in the docker-compose.yml file to postgres:12-alpine. That change is already in master, so we should be good 🥇