Align documentation generation to Django

[pauloxnet]

To maintain compatibility, we want to align documentation generation with Django's pipeline.

Since in the Django documentation requirements we are using the latest available version of Sphinx [1] we agreed with @bmispelon that it is safe to also update the version we use on the site to the latest available in order to be aligned with the pipeline that generates the Django documentation.

We should also align the commands and options used to generate documentation between what happens in the Django pipeline and what happens in the DjangoProject commands.

In the Django repository action the documentation is not generated [2], but only the spelling builder is invoked to check typos in the documentation, so there are no options to align here.

[1] https://github.com/django/django/blob/main/docs/requirements.txt#L2
[2] https://github.com/django/django/blob/main/.github/workflows/docs.yml