$ git clone -n https://src.fedoraproject.org/rpms/golang-x-crypto.git /var/lib/mock/f40-build-2595854-62746/root/chroot_tmpdir/scmroot/golang-x-crypto
Cloning into '/var/lib/mock/f40-build-2595854-62746/root/chroot_tmpdir/scmroot/golang-x-crypto'...
$ git fetch origin b879e6fc6e4fa7491c964f6a839f476dfa499007:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-x-crypto
 * [new ref]         b879e6fc6e4fa7491c964f6a839f476dfa499007 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b879e6f update to v0.19.0, close rhbz#2263280