Update Ubuntu Bionic CI shard with new Python versions (#76)
Update Ubuntu Bionic CI shard with new Python versions (#76)

Travis recently upgraded its Python versions for Ubuntu Bionic (18.04). Versions pulled from https://docs.travis-ci.com/user/reference/bionic/#python-support.
pantsbuild/setup,pantsbuild/setup,jsirois/setup,jsirois/setup,jsirois/setup,pantsbuild/setup