Allowing str and list input types in addition to None and dict.

Running 6 different Python versions (3.7 to 3.12) in parallel now.
NOTE: This is in conflict with wireviz#309, but can be resolved easily in a later PR.

GitHub Actions require an update:
- actions/upload-artifact@v3 is scheduled for deprecation on November
30, 2024.
- Similarly, v1/v2 are scheduled for deprecation on June 30, 2024. 
- Updating this comes with a breaking change in upload-artifact@v4:

Uploading to the same named Artifact multiple times.

Due to how Artifacts are created in this new version, it is no longer
possible to upload to the same named Artifact multiple times. You must
either split the uploads into multiple Artifacts with different names,
or only upload once. Otherwise you will encounter an error.

The artifact .zip files therefore have the python version added to
their name.