Tweak publishing workflow

[nstepien]

Dry-ran the publishing workflow to test things out, and tweaked the following:

• added --tag latest to ensure we can publish even pre-release versions
  • in the future it might be nice to add a choice input to confirm which npm dist-tag to publish to
  • for now we only want to push to the latest so this is fine
• because of branch protections, we can't push back to main, so now we'll only push the tag, and we'll have to merge the tag onto main manually
• removed prepublishOnly/postpublish commands from the package.json
  • we had these for the manual publishing workflow