Fix after ring-proof api change (#5126)
Ring-proof backend API changed to take some params by ref. Bandersnatch-VRF was not updated (Fixed by: https://github.com/w3f/ring-vrf/pull/92 and https://github.com/w3f/ring-vrf/pull/93)
Ring-proof backend API changed to take some params by ref. Bandersnatch-VRF was not updated (Fixed by: https://github.com/w3f/ring-vrf/pull/92 and https://github.com/w3f/ring-vrf/pull/93)