add scorecard badge to README file
add scorecard badge to README file

Signed-off-by: Joyce Brum <6533eb4252a1d3d44c780c3af60aa58935ef2d06@gmail.com>

etcd-io/etcd,ajityagaty/etcd,ajityagaty/etcd,ajityagaty/etcd,etcd-io/etcd,etcd-io/etcd