Update supported Python versions

[moggers87]

Python 3.8 ended support back in October and Python 3.13 is supported by Django 5.1

Description

• Removed Python 3.8 from tox, Github actions, etc.
• Added Python 3.13 to tox, Github actions, etc.
• Bumped up Selenium version installed for testing
• Stop testing Python 3.10 and 3.11 against Django main

Motivation and Context

How Has This Been Tested?

Ran tox locally and all tests passed

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[moggers87]

I think I'm going to hold off on this PR until Django 5.2 is released. Tests pass when run against Django main so I don't foresee any changes other than adding it to the test matrix once released.

[claudep]

I also saw some projects recently limiting the tests to the lower and higher Python versions, which should not make a big difference in test accuracy, but consumes less resources.

[claudep]

Looks good!

[claudep]

Feel free to merge this, thanks 👍