This is based on the changes in OpenStack projects like [1] in ironic.
Some options are now automatically configured by openstackdocstheme
1.20.0 and later.
- project
- html_last_updated_fmt
- latex_engine
- latex_elements
- version
- release.
[1] 1becd6dda9f61652d1ff1345898514bf0e73c0fb
Change-Id: I2ff42d5a46f99b4aeaaf1b4f5abc47cd7bbbbb00