AutoPublish Release Candidate

[teubert]

We want to submit a rc version (ends in .rc#, e.g., .rc0) to PyPi, then test it for each commit to a release branch.

Suggestion - see pypi-version to get latest release version. If to left of rc in the package.version (or setup.py) is the same, then increment rc #, otherwise add rc0 to release number. We might have to move version # to a separate file to get this to work.

See Also: nasa/progpy#48