Bump django from 1.11 to 1.11.23 in /demo-django

Bumps [django](https://github.com/django/django) from 1.11 to 1.11.23.
- [Release notes](https://github.com/django/django/releases)
- [Commits](django/django@1.11...1.11.23)

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

Author: dependabot[bot]

demo-django/requirements.txt

@@ -1 +1 @@
-Django==1.11
+Django==1.11.23