Before new release, add a summary of changes since last version to CHANGELOG.rst
pip install 'zest.releaser[recommended]'
prerelease
release
git push origin master --follow-tags
At this point Travis should start a build for the version tag and the last step
Python: 3.7 CELERY=4 COVER=1
should upload the release to pypi.
Once that's done, switch back to development:
postrelease
git push