Make amphp/windows-registry a suggested dependency

[shouze]

As it's platform related and make vendor dir heavier for nothing when not running code on Windows.

[kelunik]

That would make any app and library incompatible with Windows by default, so I'm against that.

[shouze]

not incompatible by default as it's suggested & have to be documented but I understand your argument of course.

[shouze]

The point is composer don't permit ATM to express requirements that vary depending on OS or php version, which would be great & make a more decent solution of course.

[kelunik]

Right, this is an issue Composer needs to solve first. suggest is completely broken as it doesn't allow any constraints. Yes, you can achieve that with conflicts, but it's really sub-optimal.

I very much prefer a little bit of space in favor of compatible by default.