Bump django from 3.1.1 to 3.1.2

Bumps [django](https://github.com/django/django) from 3.1.1 to 3.1.2.
- [Release notes](https://github.com/django/django/releases)
- [Commits](django/django@3.1.1...3.1.2)

Signed-off-by: dependabot[bot] <support@github.com>

test-requirements.txt

@@ -13,7 +13,7 @@ chardet==3.0.4            # via aiohttp, requests
 click==7.1.2              # via uvicorn
 coverage==5.3             # via coveralls, pytest-cov
 coveralls==2.1.2          # via -r test-requirements.in
-django==3.1.1             # via -r test-requirements.in
+django==3.1.2             # via -r test-requirements.in
 docopt==0.6.2             # via coveralls
 filelock==3.0.12          # via pytest-mypy
 h11==0.9.0                # via httpcore, uvicorn