Bump django-model-utils from 4.0.0 to 4.1.1 in /requirements/production
Bump django-model-utils from 4.0.0 to 4.1.1 in /requirements/production

Bumps [django-model-utils](https://github.com/jazzband/django-model-utils) from 4.0.0 to 4.1.1.
- [Release notes](https://github.com/jazzband/django-model-utils/releases)
- [Changelog](https://github.com/jazzband/django-model-utils/blob/master/CHANGES.rst)
- [Commits](https://github.com/jazzband/django-model-utils/compare/4.0.0...4.1.1)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>
studentenportal/web,studentenportal/web,studentenportal/web,studentenportal/web,studentenportal/web