Bump django from 1.10.7 to 1.11.28

Bumps [django](https://github.com/django/django) from 1.10.7 to 1.11.28.
- [Release notes](https://github.com/django/django/releases)
- [Commits](django/django@1.10.7...1.11.28)

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

Author: dependabot[bot]

requirements.txt

@@ -11,7 +11,7 @@ defusedxml==0.5.0
 diff-match-patch==20121119
 dj-database-url==0.4.1
 dj-static==0.0.6
-Django==1.10.7
+Django==1.11.28
 django-allauth==0.32.0
 django-appconf==1.0.2
 django-classy-tags==0.8.0