fix shellcheck warnings

[seboss666]

I saw yesterday the warnings around shellcheck, and sadly did not notice earlier. So I've reviewed and fixed the warnings regarding it, and tested locally to ensure no more warnings due to my previous changes.

[seboss666]

OK, was again too quick to check against old versions, and the "quotes around vars" break the split mechanism to validate the version matching the "arch" naming scheme. So don't merge that for now, I'll need to find other workarounds.

[seboss666]

Hello, I've finally found time to update the code to fix the logic error and skip the splitting for version check. It worked locally, so I pushed the change.

I also tried to update the action version used for the tests, to remove the errors about deprecated /deactivated functions in Github Actions. The linux test pass, but the macos fails. Unfortunately I have no Apple environment to work with locally to try to understand where the problem lies compared tu Ubuntu. So I'm opened to help for that.