message: cli: add -netinfo server version check and error message
diff: @@ -379,6 +379,11 @@ public:
  if (!batch[ID_PEERINFO]["error"].isNull()) return batch[ID_PEERINFO];
  if (!batch[ID_NETWORKINFO]["error"].isNull()) return batch[ID_NETWORKINFO];
  + const UniValue& networkinfo{batch[ID_NETWORKINFO]["result"]};
  + if (networkinfo["version"].get_int() < 209900) {
  + throw std::runtime_error("-netinfo requires bitcoind server to be running v0.21.0 and up");
  + }
  +
  // Count peer connection totals, and if m_verbose is true, store peer data in a vector of structs.
  const int64_t time_now{GetSystemTimeInSeconds()};
  int ipv4_i{0}, ipv6_i{0}, onion_i{0}, block_relay_i{0}, total_i{0}; // inbound conn counters
  @@ -436,7 +441,6 @@ public:
  }
  // Generate report header.
  - const UniValue& networkinfo{batch[ID_NETWORKINFO]["result"]};
  std::string result{strprintf("%s %s%s - %i%s\n\n", PACKAGE_NAME, FormatFullVersion(), ChainToString(), networkinfo["protocolversion"].get_int(), networkinfo["subversion"].get_str())};
  // Report detailed peer connections list sorted by direction and minimum ping time.
  