Test PRIMA.jl on new platforms

[amontoison]

@emmt You need to add CirrusCI on this repository for running the builds on Linux musl, FreeBSD and Apple M1.

[amontoison]

Note that you can use 1 instead of 1.9 here to always use the last stable release of Julia.

[codecov-commenter]

Welcome to Codecov 🎉

Once merged to your default branch, Codecov will compare your coverage reports and display the results in this comment.

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[emmt]

Note that you can use 1 instead of 1.9 here to always use the last stable release of Julia.

I'll do that. thanks for mentioning this feature.

[emmt]

... and thanks for the PR.