Automate publish to PyPI

[wnienhaus]

To make it easier to publish py-esp32-ulp to PyPI, we can automate it.
This would allow automatic publishing (by triggering a Github Action) every time a new Release is created in Github.

So far I have tested this approach in: https://github.com/wnienhaus/ujqtvms in the publish.yml workflow.

This could also make it easier for various maintainers to publish without needing to share PyPI credentials or documentation on how to manually do this.