Django-sendfile2

- Fix reflected file download vulnerability
- Add support for spaces in filenames

- Fixed Django 4.0 compatibility
- Add support for Python 3.10
- Remove support for Python 3.5 and 3.6
- Remove support for Django 3.1

This release contains a fix for https://github.com/moggers87/django-sendfile2/security/advisories/GHSA-6r3c-8xf3-ggrr. Thanks to Gianluca Pacchiella for reporting this issue and for providing the initial patch.

- Fixed issue where django-sendfile could serve *any* file, even if it was
outside `SENDFILE_ROOT`. `SEDNFILE_ROOT` is now required for all
backends.

- Fix issue with versioneer not being updated about the package name change
- tox now does a proper sdist and install to avoid this in future

The following is from version 0.5.0 which was tagged but not released:

- Rename Python package from ``sendfile`` to ``django_sendfile``
- This will require changing ``SENDFILE_BACKEND``, ``INSTALLED_APPS``, and
any imports
- Remove code used to support Python 2.7
- Add support for the latest versions of Django and Python