Provide or point at a podman or docker build environment for windows

[hammerandtongs]

I've noticed that people(me included) have trepidation about adopting gtk based on whether they can get a working windows build.

This could be alleviated with some documentation or landing page guidance to use podman/docker -

https://github.com/NoraCodes/rust-mingw64-gtk-docker/issues/1#issuecomment-559894808

https://github.com/rust-embedded/cross

Sorry this is not a more developed bug as I'm using another gui atm.

[synth-ruiner]

I've also tried both of those Docker solutions this week, and haven't had any luck cross-compiling for Windows yet. Would be great if there was an official/actively-maintained container/VM image for this purpose.