Cease making win32 builds for S3_1 and later
We've stopped making any public builds of win32 target from S3_1 and later. As of now, I still do occasional local test build against that target, as our msys2 snapshot still supports it. Plan is to drop the support from next msys2 environment after 220903 (currently in testing)
I don't think anybody needs 32bit Windows builds any more, especially by the time 3.1.0 gets released. Save the resources by ceasing to build win32 builds from S3_1 and master.
As it's likely that some msys2 environment will be backported to use in S3_0, we can't drop support for win32 from them yet. We can do that once the new msys2 environment versions will be used for S3_1+ only.
As part of #43200, this has also been posted to http://forum.freeciv.org/f/viewtopic.php?f=14&t=92047