Add %ifarch %arm aarch64 BuildRequires: binutils-gold to fix
/usr/lib64/go/{version}/pkg/tool/linux_arm64/link: running gcc failed: exit status 1
collect2: fatal error: cannot find 'ld'-

NB: Some automated OBS tooling introducing incidental diff by moving:
BuildRequires: golang(API) = 1.12 below
BuildRequires: go1.12 >= 1.12.9
That is not a change I committed in my branch, but that is what shows up
in this SR diff. I've reproduced it several times now.