Associate .py with python on Windows

Description:
Associate .py with python on Windows when running actions/setup-python@v4

Justification:
I want to test that my .py have executable permission set relying on shebang line. That passes on Ubuntu. Windows doesn't care about file permissions set by git, but it has a different mechanism:
https://docs.python.org/3/faq/windows.html#how-do-i-make-python-scripts-executable

On Windows, the standard Python installer already associates the .py extension with a file type (Python.File) and gives that file type an open command that runs the interpreter (D:\Program Files\Python\python.exe "%1" %*).

and https://docs.python.org/3/using/windows.html#from-file-associations:

The launcher should have been associated with Python files (i.e. .py, .pyw, .pyc files) when it was installed.

Apparently that doesn't happen when using actions/setup-python@v4

Are you willing to submit a PR?
No

Inizia dal percorso di configurazione Windows per actions/setup-python@v4 e consulta la documentazione Python collegata sulle associazioni di file di Windows. Verifica in che modo l’azione installa o rende attualmente disponibile Python, quindi verifica che uno script .py che utilizza uno shebang possa essere eseguito in un’azione Windows; il lavoro è completato quando l’associazione funziona in modo coerente in quel contesto.