CI doesn't make a Win32 build

[indigodarkwolf]

Right now, CI only makes one Windows build, and its 64-bit only. A 32-bit build could be a nice-to-have if someone were interested in doing it, and there's at least one user that was trying to run x16emu on a 32-bit Windows installation, and on its face it seems like this is the sort of thing that should be low-maintenance for future builds, since there is very little reason x16emu shouldn't be able to run on a 32-bit machine.

I made a token effort on a separate fork, got as far as the link step and library incompatibilities, but I lack the familiarity with mingw to really troubleshoot the process meaningfully.

[mooinglemur]

Can be closed by #469