Maybe create a matrix of tests in the cscs.yml file

[pfebrer]

I think this is fine for now to unlock other work, but I'd still prefer if we can do something closer to https://github.com/metatensor/metatrain/blob/main/.github/workflows/architecture-tests.yml, where only the architecture name is duplicated, but the test setup is the same for all. Can you open an issue about it?

Originally posted by @Luthaf in #1167 (comment)

I'm not so sure there are benefits in doing this though 😅

[Luthaf]

It makes it easier to add/remove architectures to metatrain! So not extremely urgent, but nice to have