Bump django from 2.0.6 to 2.2.18 in /demo
Bump django from 2.0.6 to 2.2.18 in /demo

Bumps [django](https://github.com/django/django) from 2.0.6 to 2.2.18.
- [Release notes](https://github.com/django/django/releases)
- [Commits](https://github.com/django/django/compare/2.0.6...2.2.18)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>
Tivix/django-cron