Update circuit relay configuration to use v2 protocol

[FlorianRuen]

When trying to use the Circuit Relaying example (found here in the repo), the config doesn't take the v2 procotol into account

"DisableRelay": false,
 "EnableRelayHop": true

Not available anymore and return an error / warning if the daemon launched using this configuration

ipfs  | 2022-02-17T13:00:55.456Z        FATAL   core:constructor    node/groups.go:138       The `Swarm.EnableRelayHop` config field is ignored.
ipfs  | Use `Swarm.RelayService` to configure the circuit v2 relay.
ipfs  | If you want to continue running a circuit v1 relay, please use the standalone relay daemon: https://github.com/libp2p/go-libp2p-relay-daemon (with RelayV1.Enabled: true)