Replace pip.main() in installer

[paigevegna]

The installer script uses the older version of the pip package. Specifically, the code uses the pip.main() function, which has been removed since pip version 10.

A quick workaround would be the callable-pip package, a wrapper around pip that allows you to use the pip.main() syntax that's currently there. The long-term solution would be to either using subprocess to call pip or using import statements.

[virtuald]

Thanks for noticing this. I'll probably fix it once I start deploying RobotPy to my beta roborio image, unless someone else fixes it first!

Subprocess is probably the best way to go. Something like subprocess.call([sys.executable, '-m', 'pip'] + *args )...

[auscompgeek]

Huh, I could've sworn we fixed this.

[virtuald]

Ah yes, duplicate of #15 . @paigevegna if you upgrade your version of the installer it should work for you!