Bump django-extensions from 2.1.7 to 2.1.9
Bump django-extensions from 2.1.7 to 2.1.9

Bumps [django-extensions](https://github.com/django-extensions/django-extensions) from 2.1.7 to 2.1.9.
- [Release notes](https://github.com/django-extensions/django-extensions/releases)
- [Changelog](https://github.com/django-extensions/django-extensions/blob/master/CHANGELOG.md)
- [Commits](https://github.com/django-extensions/django-extensions/compare/2.1.7...2.1.9)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
ebmdatalab/openprescribing,annapowellsmith/openpresc,ebmdatalab/openprescribing,annapowellsmith/openpresc,ebmdatalab/openprescribing,annapowellsmith/openpresc,annapowellsmith/openpresc,ebmdatalab/openprescribing