Bump django from 1.11.29 to 4.2.16 in /demo-django

Bumps [django](https://github.com/django/django) from 1.11.29 to 4.2.16.
- [Commits](django/django@1.11.29...4.2.16)

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

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

demo-django/requirements.txt

@@ -1 +1 @@
-Django==1.11.29
+Django==4.2.16