Add file to the reno documentation build to show release notes for
stable/stein.
Use pbr instruction to increment the minor version number
automatically so that master versions are higher than the versions on
stable/stein.
Change-Id: Ib83d3c34e2e29296ff8271cfd28af08b7fa83d63
Sem-Ver: feature
OpenStack Release Bot
46e4ab1bd0