Defaulting to running Python version if project .python-version is missing

[JAMoreno-Larios]

I was having issues running the integration test on my repo. After checking the backtrace, I found out that local.py could not build the Docker image if .python-version is missing since MY_UV_VERSION is set to None.

I address this issue by sourcing the Python version running the script.

Checklist when adding a new endpoint

• Added new endpoint to the README.md
• Ensured that my endpoint name does not repeat the name of the client. Wrong: client.users.get_user(), Correct: client.users.get()
• Typed the returned JSON using TypedDicts in berserk/types/, example
• Written tests for GET endpoints not requiring authentification. Documentation, example
• Added the endpoint and your name to CHANGELOG.md in the To be released section (to be created if necessary)

[kraktus]

thanks!