We want to default to running all tox environments under python 3, so
set the basepython value in each environment.
We do not want to specify a minor version number, because we do not
want to have to update the file every time we upgrade python.
We do not want to set the override once in testenv, because that
breaks the more specific versions used in default environments like
py35 and py36.
Update the tox configuration to pull in the openstack
upper-constraints.txt when running releasenotes. This will
fix the releasenotes job that is currently failing due to
a new version of sphinx. Additionally this change includes
updates from puppet-modulesync-configs.
ReNo  is the release management tool in OpenStack.
This patch adds the basic structure to start using it.
* Update .gitignore
* Add releasenotes/ dir and basic files
* Add python files: setup.cfg, setup.py, test-requirements.txt and