[Briefcase] Update the push to central CLI block

https://github.com/opendatakit/briefcase/pull/795 introduces changes to the help block that need to be updated in the docs

Start by reviewing Briefcase pull request #795 and searching the docs repository for the push-to-central CLI help block. Update the documentation to match the help changes introduced there, then verify the affected Sphinx documentation builds successfully.

Written by the indexing model from the issue text.