Convenient way of specifying python version

[zsimic]

Would be very convenient if a short form for --python-version was available, like -p, and if major.minor was accepted, such that we could run:

honesty deps -p3.7 requests

[thatch]

Yeah, with the caveat that it will pick an arbitrary patch version (probably 0), this is easily possible. 0.3.0b1 also defaults to the current python version, because that seemed better than defaulting to 3.7 :)