fix and update packaging

* drop empty setup.py which "breaks" on incomplete build envs
* use the build package to build the dist
* update the gh workflow to use it

fixup noise from pre-commit

pyproject.toml

@@ -1,6 +1,5 @@
 [build-system]
 requires = [
-  # sync with setup.py until we discard non-pep-517/518
   "setuptools>=45.0",
   "setuptools-scm[toml]>=6.2.3",
   "wheel",