https://bugzilla.redhat.com/show_bug.cgi?id=2181039
--- Comment #5 from fedora.dm0@gmail.com --- Thanks, spec and SRPM are updated. (The SRPM URL switched to fc38.)
I actually started with cargo-rpm-macros as the dependency but changed it to follow the guidelines, so I suppose this line needs to be updated:
All Rust packages MUST have BuildRequires: rust-packaging.