message: action: fix implicit cast
diff: @@ -462,7 +462,7 @@ void ActionImpl::set_actuator_async(
  command.params.param6 = value;
  break;
  }
  - command.params.param7 = index / 6;
  + command.params.param7 = static_cast<float>(index) / 6.0f;
  _parent->send_command_async(
  command, [this, callback](MavlinkCommandSender::Result result, float) {
  