Revisiting VERSION for Python subpackage

[John Snow]

Hi Peter: In the past, you expressed hesitation over adding another 
VERSION file to ./python/, preferring we single-source it somehow.

For now, I believe I will be pursuing a version of 0.6.0.0a1 to indicate 
the subpackage is in a beta state, but otherwise tied/related to the 
QEMU 6.0 release. I plan to change this to '0.6.0' during the release 
candidate phase.

(It also leaves open the door to begin independent versioning schemes 
later if we want to fork useful parts of the library out.)

Due to the way python packaging works, there is currently no way to 
refer to files *above* the python package root because files are copied 
out to a temporary, isolated environment. I do not believe there is any 
way for me to avoid creating a second file.

I wanted to check and make sure this wasn't going to be a no-go.

--js