Add file to the reno documentation build to show release notes for stable/2023.2. Use pbr instruction to increment the minor version number automatically so that master versions are higher than the versions on stable/2023.2. Sem-Ver: feature Change-Id: I89e898b8bf871d134a403dd0dc053a7028620f9d Signed-off-by: OpenStack Release Bot <infra-root@openstack.org>