Bump djangorestframework from 3.10.3 to 3.11.2

Bumps [djangorestframework](https://github.com/encode/django-rest-framework) from 3.10.3 to 3.11.2.
- [Release notes](https://github.com/encode/django-rest-framework/releases)
- [Commits](encode/django-rest-framework@3.10.3...3.11.2)

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

Author: dependabot[bot]

requirements.txt

@@ -6,7 +6,7 @@ certifi==2019.9.11
 chardet==3.0.4
 Django==2.2.13
 django-cors-headers==3.1.0
-djangorestframework==3.10.3
+djangorestframework==3.11.2
 idna==2.8
 kombu==3.0.37
 psycopg2-binary==2.8.2