Relative path, .:/data, does not work on windows

[mnowster]

Due to us now using splitdrive in split_path_mapping it reads the .: as a drive, rather than a relative path.

[mnowster]

For reference, this is the splitdrive code. https://github.com/python/cpython/blob/829b49cbd2e4b1d573470da79ca844b730120f3d/Lib/ntpath.py#L120

[atrauzzi]

Awesome! What's my best option for pulling down the latest change and trying it out?

[mnowster]

@atrauzzi if you hang tight, there should be a release candidate sooooooooooon :)