Bump django from 1.10.3 to 1.11.23

Bumps [django](https://github.com/django/django) from 1.10.3 to 1.11.23.
- [Release notes](https://github.com/django/django/releases)
- [Commits](django/django@1.10.3...1.11.23)

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

requirements.txt

@@ -1,4 +1,4 @@
-Django==1.10.3
+Django==1.11.23
 pytest==3.1.2
 pytest-cov==2.5.1
 pytest-django==3.1.2