I'd like to try something more: Avoid the repetition of the lmod version.
It seems you can generate a whole matrix from within a job step: https://docs.github.com/en/actions/reference/context-and-expression-syntax-for-github-actions#example-returning-a-json-object

But what we just need here is something we can access with ${{}}, e.g. an env variable.
I'll try that later, so hold up the merge please :)

I'd like to try something more: Avoid the repetition of the lmod version.
It seems you can generate a whole matrix from within a job step: https://docs.github.com/en/actions/reference/context-and-expression-syntax-for-github-actions#example-returning-a-json-object

But what we just need here is something we can access with ${{}}, e.g. an env variable.
I'll try that later, so hold up the merge please :)

OK! :)

@Flamefire Once you're happy with the changes, I'll need to re-configure the test configurations that are required to pass (which is why there's a bunch of orange dots sitting there "waiting" right now).

I think this works now. What do you think about this approach?
Alternative:

env:
  LMOD_7: Lmod-...
  ...
  modules_tool: [${env.LMOD_7}, ...]

That's a bit shorter but sets those as actual env variables, so my current approach feels "more right"