Bump django-grappelli from 2.14.4 to 2.15.1
Bump django-grappelli from 2.14.4 to 2.15.1

Bumps [django-grappelli](https://github.com/sehmaschine/django-grappelli) from 2.14.4 to 2.15.1.
- [Release notes](https://github.com/sehmaschine/django-grappelli/releases)
- [Changelog](https://github.com/sehmaschine/django-grappelli/blob/master/docs/changelog.rst)
- [Commits](https://github.com/sehmaschine/django-grappelli/compare/2.14.4...2.15.1)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
michaelmior/pylinks,michaelmior/pylinks,michaelmior/pylinks