Publish using the new PyPI and do a release to test

[Adi Roiban]

The details are here

https://docs.pypi.org/trusted-publishers/using-a-publisher/

To actually test this, we will need to trigger a full release

And with the full release, we can drop support for python 3.7... even if it's not EOL yet.

Byt this will be the last release to support 3.7