Outdated readme in just-0.12.0-windows-x86_64

[reconeazaretzky]

Hey @maciejwalkowiak the readme in the windows zip package is referring to this tool as fly instead of just

[maciejwalkowiak]

Thanks for pointing that out. Readme should be removed as it's heavily outdated.

Fly is the first name for Just from times when it was meant to be a maven plugin.