Bump django from 3.0.6 to 3.0.7 in /backend/requirements

Bumps [django](https://github.com/django/django) from 3.0.6 to 3.0.7.
- [Release notes](https://github.com/django/django/releases)
- [Commits](django/django@3.0.6...3.0.7)

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

Author: dependabot[bot]

backend/requirements/base.txt

@@ -11,7 +11,7 @@ daphne==2.5.0
 graphene-django==2.10.1
 django-graphql-jwt==0.3.1
 
-Django==3.0.6
+Django==3.0.7
 django-filter==2.2.0
 djangorestframework==3.11.0
 djangorestframework_simplejwt==4.4.0