Update GitHub Actions' workflows

[nnsnodnb]

• Updated steps.
• Improved getting full python version from actions/setup-python@4.
• set-output was deprecate.
• poetry install added --sync argument.

Thank you!

[mpeteuil]

Hey @nnsnodnb! Thanks for the contributions to update these deprecations! There's one change that needs to be made, otherwise this looks.

[mpeteuil]

Thanks @nnsnodnb. The reason this was failing was outlined and resolved in #21. If you either rebase against main or merge main into these changes then these tests should run as expected and we can get your contributions merged 😄

[nnsnodnb]

Thank you for resolving.
I have rebased it, so please check again.

[mpeteuil]

Thanks again for updating these!