Comment 1 for bug 1813037

I just hit this too.

It'd be good to address this in launchpad, but meanwhile I found a simple (though nasty) way to work around this PPA upload check when using dpkg 1.19.3 or newer. Passing -DBinary=dummy to dpkg-genchanges (or --changes-option=-DBinary=dummy to dpkg-buildpackage) results in a *_source.changes containing "Binary: dummy" which passes the PPA upload check and the package then builds successfully, giving the binary packages it should (the contents of this header doesn't seem to need to match the packages which actually get built).