Force 'https://www.python.org/' URLs for ReleaseFile properties

[sethmlarson]

Description

Adds a new CheckConstraint that forces all URLField fields on ReleaseFile model to not accept URLs that don't start with http(s)://www.python.org/.

[hugovk]

Locally, if I change the URL for a file of an existing release to www.example.com/[etc], clicking save correctly gives an error:

Constraint “only_python_dot_org_urls” is violated.

Also when creating a new release with a file.

But can we make that error more descriptive?

I don't need to know what a "constraint" is; tell me what's not allowed and what is.

[sethmlarson]

Done in 93e2795, the new message is "All file URLs must begin with 'https://www.python.org/'".

[hugovk]

Thanks!

[sethmlarson]

FYI: The Lint action failed to install, I ran make lint locally and received no errors.

[hugovk]

Re-ran lint and passed: https://github.com/python/pythondotorg/actions/runs/22413902653/job/64899885730