chore(tox): add pypi-publish

tox.ini

@@ -23,3 +23,18 @@ commands = flake8
 [flake8]
 max-line-length = 120
 exclude = cubicweb_geocoding/migration/*,.tox/*
+
+[testenv:pypi-publish]
+basepython = python3
+skip_install = true
+whitelist_externals = rm
+deps =
+  twine
+passenv =
+  TWINE_USERNAME
+  TWINE_PASSWORD
+commands =
+  rm -rf build dist .egg .egg-info
+  python3 setup.py sdist bdist_wheel
+  twine check dist/*
+  twine upload --skip-existing dist/*