Comment 1 for bug 1889779

According to e.g. comment in https://serverfault.com/questions/726764/migration-of-ebtables-arp-rule-to-nftables it seems that nftables have no implemented syntax for source and destination ipv4 address in arp tables right now.

So solution/workaround for this issue for us would be to switch to ebtables-legacy on Ubuntu Focal, at least for now.