Update ffi dependency

[Sesa1988]

Hi,

I'm getting following error:

Because package_info_plus >=3.0.0 depends on ffi ^2.0.1 and every version of url_protocol depends on ffi ^1.0.0, package_info_plus >=3.0.0 is incompatible with url_protocol.

It would be nice if this would be updated :)

[ihorkozar]

@lsegal It is enough to update win32: #3