Support macOS and Windows

[MyBuzzTechnologies]

Thanks for the great plugin. Could you please look to add support for macOS and Windows so it's truly a universal package please?

[tom-ludwig]

@MyBuzzTechnologies
I love the idea of using the package on macOS and Windows. Could you please reopen your issue here: https://github.com/activcoding/disk_space_2?
Since this package hasn't been updated in 2 years and the maintainers haven't responded to any issues or pull requests, I created a new repository: https://github.com/activcoding/disk_space_2. The updated package, which should work, is available here: https://pub.dev/packages/disk_space_2.