params: enable DNS discovery on Sepolia too

params/bootnodes.go

@@ -116,6 +116,8 @@ func KnownDNSNetwork(genesis common.Hash, protocol string) string {
 		net = "rinkeby"
 	case GoerliGenesisHash:
 		net = "goerli"
+	case SepoliaGenesisHash:
+		net = "sepolia"
 	default:
 		return ""
 	}