$ git clone -n https://src.fedoraproject.org/rpms/rust-gtk3-macros /var/lib/mock/f42-build-3429020-45391/root/chroot_tmpdir/scmroot/rust-gtk3-macros
Cloning into '/var/lib/mock/f42-build-3429020-45391/root/chroot_tmpdir/scmroot/rust-gtk3-macros'...
$ git fetch origin 1d06c8a75b0acf975f4ae5043dfd31e84407dfc3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-gtk3-macros
 * [new ref]         1d06c8a75b0acf975f4ae5043dfd31e84407dfc3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1d06c8a Update to version 0.18.2; Fixes RHBZ#2331132