Bump GH actions

[svlandeg]

Description

• Bump GH actions
  • checkout: v3 -> v4
  • setup-python v4: -> v5
• Don't forcefully set x64 but build for the native platform instead.
• Update pytest to 8.2 and update test accordingly, cf https://docs.pytest.org/en/stable/deprecations.html#pytest-importorskip-default-behavior-regarding-importerror
• Revert macOS runner to v13 instead of latest

Types of change

Bump

Checklist

• I confirm that I have the right to submit this contribution under the project's MIT license.
• I ran the tests, and all new and existing tests passed.
• My changes don't require a change to the documentation, or if they do, I've added all required information.