chore(tox): add pypi-publish

tox.ini

@@ -24,3 +24,18 @@ deps =
   check-manifest
 commands =
   {envpython} -m check_manifest {toxinidir}
+
+[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/*