build(deps): bump django from 3.0.2 to 3.1.13

Bumps [django](https://github.com/django/django) from 3.0.2 to 3.1.13.
- [Release notes](https://github.com/django/django/releases)
- [Commits](django/django@3.0.2...3.1.13)

---
updated-dependencies:
- dependency-name: django
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements.txt

@@ -1,6 +1,6 @@
 # Core
 pytz==2019.3
-Django==3.0.2
+Django==3.1.13
 django-configurations==2.2
 gunicorn==20.0.4
 newrelic==5.4.1.134