Bump django from 4.0.4 to 4.0.8 in /demo-django

Bumps [django](https://github.com/django/django) from 4.0.4 to 4.0.8.
- [Release notes](https://github.com/django/django/releases)
- [Commits](django/django@4.0.4...4.0.8)

---
updated-dependencies:
- dependency-name: django
  dependency-type: direct:production
...

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

Author: dependabot[bot]

demo-django/requirements.txt

@@ -1,2 +1,2 @@
-Django==4.0.4
+Django==4.0.8
 python3-saml