tox.ini refactoring

[marcofavoritobi]

Proposed changes

This PR applies two major changes to the tox.ini specification.

• 1f26c4a: This commit fixes a subtle bug: "commands:" is replaced by "commands = " in py3.8-nb env. Before this change, the commands configuration was not actually overwritten. The CI did not fail because the test execution defaulted to testenv...
• 3cc3bf4: use py3{py-minor-version} format rather than py3.{py-minor-version} for testenv names. This convention is more "tox-friendly", since an environment with 'py$MAJOR$MINOR' in its name will use the Python interpreter at version $MAJOR.MINOR as base python. In particular, in this way, we could avoid the repetition of different testenv configurations which only differ by the basepython variable. This change required a workaround in the GitHub Actions workflow configuration,

Fixes

n/a

Types of changes

What types of changes does your code introduce?
Put an x in the boxes that apply

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

Put an x in the boxes that apply.

• I have read the CONTRIBUTING doc
• I am making a pull request against the develop branch (left side). Also you should start your branch off our develop.
• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works

Further comments

n/a