Respect .python-version as suggested by pyenv (and pyenv-virtualenv)

[muuvmuuv]

There are several issues about not finding the correct python interpreter, but none about the fact that a simple .python-version file holds the version or virtualenv name that this extension can simply parse and select the interpreter based on it.

[karthiknadig]

Thank you for the suggestion! We have marked this issue as "needs decision" to make sure we have a conversation about your idea. We plan to leave this feature request open for at least a month to see how many 👍 votes the opening comment gets to help us make our decision.

[bersbersbers]

I'm not sure if issuing pyenv local || pyenv global may be more robust, though. @muuvmuuv, I have this problem a lot, could you list some of these other issues here?

[tigerhawkvok]

On Windows at least, you could get around this by allowing the default interpreter to be the pyenv shim, but it's not allowed to be selected as the default Python.

[anthonykim1]

Looks like a dup of #1167 This should've been resolved with #23094, I believe. Are folks still experiencing this issue? I'm going to close the issue but please let us know if you are still suffering from this, I can reopen this.