Initial release
To release a new version of spyder-kernels on PyPI:
* Close the respective milestone on Github
* git checkout 3.x
* git fetch upstream && get merge upstream/3.x
* Update CHANGELOG.md with `loghub spyder-ide/spyder-kernels -m vX.X.X`
* git clean -xfdi
* Update `_version.py` (set release version, remove 'dev0')
* git add . && git commit -m 'Release X.X.X'
* python setup.py sdist
* python setup.py bdist_wheel
* twine check --strict dist/*
* twine upload dist/*
* git tag -a vX.X.X -m 'Release X.X.X'
* Update `_version.py` (add 'dev0' and increment patch)
* git add . && git commit -m 'Back to work'
* git push upstream 3.x
* git push upstream --tags