Have a workflow for test publishing Apio in PyPi test instance

[zapta]

We have a workflow that pushes successfully to PyPi main instance https://github.com/FPGAwars/apio/actions/workflows/publish-to-pypi.yaml . This issue is for adding similar publishing capabilities to the PyPi test instance so we can test before we publish 'for real'. This can be a new workflow or the existing workflow with user input to select the target instance.

@Obijuan, can you give me access in the test instance https://test.pypi.org/project/apio? My user name on PyPi test is also zapta. https://test.pypi.org/user/zapta

[zapta]

Hi @Obijuan, can you add as a maintainer of the 'apio' package in the PyPi test instance? Details above.