add missing BuildRequires: pkgconfig(protobuf) (new optional dep in 20.12)
* Sun Feb 07 2021 Kevin Kofler <Kevin@tigcc.ticalc.org> - 1:20.12.2-3
- add missing BuildRequires: pkgconfig(protobuf) (new optional dep in 20.12)
(20.08 and older do not ask for this.)