Update tox requirement from <2.10,>=2.9 to >=2.9,<3.15
Update tox requirement from <2.10,>=2.9 to >=2.9,<3.15

Updates the requirements on [tox](https://github.com/tox-dev/tox) to permit the latest version.
- [Release notes](https://github.com/tox-dev/tox/releases)
- [Changelog](https://github.com/tox-dev/tox/blob/master/docs/changelog.rst)
- [Commits](https://github.com/tox-dev/tox/compare/2.9.0...3.14.0)

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