Cannot use Unity 6+

[CDTR-MattConroy]

When a version of Unity 6 or higher is installed (i.e. with a version number 6000.x.x), Cake.Unity prints the following warning and will not allow those versions of Unity to be used:

Unity Editor file version 6000.0.2.27625 is incorrect.
Expected first two numbers to be positive and third one to be non negative.
Path: C:/Program Files/Unity/Hub/Editor/6000.0.2f1/Editor/Unity.exe

[codewing]

I've created a pr for this #77
Seems to be a windows-only issue btw since windows and mac don't do the version checks