chore(tox): add pypi-publish

tox.ini

@@ -58,3 +58,18 @@ python_files = *test_*.py
 deps =
   mypy >= 0.761
 commands = mypy --ignore-missing-imports yams
+
+[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/*