feat: default `py_runtime` version info to `--python_version`#2198

rickeylev merged 3 commits intobazel-contrib:mainbazel-contrib/rules_python:mainfrom

rickeylev:feat.default.runtime.version.to.pyver.flagrickeylev/rules_python:feat.default.runtime.version.to.pyver.flagCopy head branch name to clipboard