Test against 3.13

[ap--]

As long as #193 is not implemented, we need to get ahead of the Python version testing, to avoid an overly long transition period (like for UPath 0.1.x to 0.2.x).

Actual:

• ...
• 3.13.0 beta 2: Wednesday, 2024-06-05

Expected:

• 3.13.0 beta 3: Tuesday, 2024-06-25
• 3.13.0 beta 4: Tuesday, 2024-07-16
• 3.13.0 candidate 1: Tuesday, 2024-07-30
• 3.13.0 candidate 2: Tuesday, 2024-09-03
• 3.13.0 final: Tuesday, 2024-10-01