Bump djangorestframework from 3.7.4 to 3.11.2

Bumps [djangorestframework](https://github.com/encode/django-rest-framework) from 3.7.4 to 3.11.2.
- [Release notes](https://github.com/encode/django-rest-framework/releases)
- [Commits](encode/django-rest-framework@3.7.4...3.11.2)

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

Author: dependabot[bot]

requirements.txt

@@ -4,7 +4,7 @@ django-taggit==1.0
 Django==2.2
 django-modeltranslation==0.14
 
-djangorestframework==3.7.4
+djangorestframework==3.11.2
 
 # Recommended components (require additional setup):
 psycopg2==2.8.5