Bump isort from 4.3.21 to 5.1.1
Bump isort from 4.3.21 to 5.1.1

Bumps [isort](https://github.com/timothycrosley/isort) from 4.3.21 to 5.1.1.
- [Release notes](https://github.com/timothycrosley/isort/releases)
- [Changelog](https://github.com/timothycrosley/isort/blob/develop/CHANGELOG.md)
- [Commits](https://github.com/timothycrosley/isort/compare/4.3.21...5.1.1)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
django-oscar/django-oscar,django-oscar/django-oscar,django-oscar/django-oscar,solarissmoke/django-oscar,solarissmoke/django-oscar,django-oscar/django-oscar,solarissmoke/django-oscar,solarissmoke/django-oscar