Add coursier package

[JD557]

It would be pretty cool to have scalals in https://github.com/coursier/apps
That would make the installation much easier (just cs install --contrib scalals).

You can see https://github.com/coursier/apps/blob/main/apps-contrib/resources/sn-bindgen.json for an example with native binaries.

[avdv]

Good call! Does that mean scalals needs to be published to some repository first?

[JD557]

That's a good question. I don't know, but the documentation does mention "In order for your application to be install-able via install, it should be published to Maven / Ivy repositories.", so I guess that's the case.

[avdv]

I am just using jitpack.io to serve the version information needed by coursier and created a PR: coursier/apps#225