$ git clone -n https://src.fedoraproject.org/rpms/golang-github-prometheus-client.git /var/lib/mock/f40-build-1517684-23912/root/chroot_tmpdir/scmroot/golang-github-prometheus-client
Cloning into '/var/lib/mock/f40-build-1517684-23912/root/chroot_tmpdir/scmroot/golang-github-prometheus-client'...
$ git fetch origin 3c13e2dbf2906678909ff20ed21c27a1bb49d7fd:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-github-prometheus-client
 * [new ref]         3c13e2dbf2906678909ff20ed21c27a1bb49d7fd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3c13e2d Update to 1.19.0 - Closes rhbz#2266727