Update Scala to 2.12.16 / 2.13.8 / 3.1.3, Scala Native to 0.4.5, and enable Scala 3 Scala Native support

[alexarchambault]

I'd be ok to split in several commits or PRs if needed... (Merging some Scala Steward prior to this one would work too, I'll just rebase.)

[kiendang]

Thanks for this @alexarchambault. I remember trying ScalaPy with a newer version of Scala Native and got error with every version > 0.4.0 when inside virtualenv which is not included in CI here. If I remember correctly it's probably because adding support for virtualenv in #200 requires WString and it interferes with wchar_t* which was added in Scala Native after 0.4.0?

If you have time to check if it works for virtualenv with your local ScalaPy with the bumped dependencies that would be great, but later we probably should add CI for virtualenv here anyway.

I'm currently looking for the fastest way to check this locally because it's a bit convoluted. Will add another comment here when I figure this out.

[kiendang]

Ok so I think the fastest way to test this is to create a minimal ScalaPy project with Scala Native, create a virtualenv and then run

export SCALAPY_PYTHON_PROGRAMNAME=path/to/your/virtualenv/Python/executable
sbt run

the ScalaPy code inside the project can just be println(py.module("sys").executable) to check if it prints out the correct path to the virtualenv Python executable.

Sorry I'm not with my own computer right now so cannot check this myself. Will take a closer look when I can.

[shadaj]

Code changes look great! I think we'll wait for @kiendang to take a look at Scala Native + Virtualenv support first though before merging.

[kiendang]

Just check locally and everything works fine 👍