Bump django from 2.1.7 to 2.1.11

Bumps [django](https://github.com/django/django) from 2.1.7 to 2.1.11.
- [Release notes](https://github.com/django/django/releases)
- [Commits](django/django@2.1.7...2.1.11)

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

Author: dependabot[bot]

requirements.txt

@@ -4,7 +4,7 @@ colour==0.1.5
 chardet==3.0.4
 coverage==4.5.3
 dj-database-url==0.5.0
-Django==2.1.7
+Django==2.1.11
 django-cloud-browser==0.5.0
 django-filter==2.0.0
 django-heroku==0.3.1