[CI] Fix the compilation on Windows

[amontoison]

@odow @cvanaret
HiGHS provides some configuration files for CMake, making it easier to detect when compiling it with other libraries like Uno.

The issue is that these configuration files use libuno.dll.a on Windows as an entry point for linking.
A file *.dll.a is an import library (neither static nor shared) — see my explanation here.
If we use -DHIGHS=${libdir}/libhighs.dll, we create another entry point that leads to duplicate symbols during the linking phase.

I modified the files build_tarballs_*.jl so that we use the import library of HiGHS on Windows to ensure a single entry point.

After merging this PR, Charlie, you can retrigger the CI build by forcing the tag with:

git tag v1.3.0 -f
git push --tags -f