Bump djangorestframework from 3.14.0 to 3.16.0

Bumps [djangorestframework](https://github.com/encode/django-rest-framework) from 3.14.0 to 3.16.0.
- [Release notes](https://github.com/encode/django-rest-framework/releases)
- [Commits](encode/django-rest-framework@3.14.0...3.16.0)

---
updated-dependencies:
- dependency-name: djangorestframework
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

requirements.txt

@@ -94,7 +94,7 @@ django-ga-context==0.1.0
 django-impersonate==1.9.1
 django-registration-redux==2.13
 django-crispy-forms==2.4  # djangorestframework
-djangorestframework==3.14.0
+djangorestframework==3.16.0
 django-smtp-ssl==1.0
 
 ctlsettings==0.4.2