[CI] Add build shards to mingw-w64 workflow

[straight-shoota]

No description provided.

[ysbaddaden]

A couple errors on CI:

Missing libyaml:

mingw32/bin/ld.exe: cannot find -lyaml (this usually means you need to install the development package for libyaml): No such file or directory

Missing tag version for downloading the molinillo dep:

curl -L "https://github.com/crystal-lang/crystal-molinillo/archive/v.tar.gz"

☝️ maybe we should vendor the dependency, just like we vendor them for crystal?

[straight-shoota]

Now the build was successful 🚀

[ysbaddaden]

Yeah, apparently all it was missing was libyaml 🤷

[ysbaddaden]

LGTM

[HertzDevil]

This is simply running make twice at the Crystal repository root because no working directory is supplied here, so the build artifacts still have neither shards.exe nor libyaml-0-2.dll

[straight-shoota]

Oh I had already fixed this, but apparently never submitted the PR 🤦 Here it is: #15451

The release tarball for 1.15.1 was created from the branch with the fix, so that does work.