add: mqtt添加心跳间隔设置函数luat_mqtt_set_keepalive

components/network/libemqtt/luat_mqtt.h

@@ -179,11 +179,12 @@ int luat_mqtt_set_triad(luat_mqtt_ctrl_t *mqtt_ctrl, const char* clientid, const
 int luat_mqtt_set_rxbuff_size(luat_mqtt_ctrl_t *mqtt_ctrl, uint32_t rxbuff_size);
 
 /**
- *@brief 设置MQTT服务器信息、加密信息函数
+ *@brief 设置MQTT服务器 心跳时长 
  *@param mqtt_ctrl luatos_mqtt对象实例
- *@param opts 结构体MQTT服务器信息、加密信息函数
+ *@param keepalive keepalive 单位s
  *@return 成功为0，其他值失败
  */
+int luat_mqtt_set_keepalive(luat_mqtt_ctrl_t *mqtt_ctrl, uint32_t keepalive);
 
 /**
  *@brief 手动发起重连

components/network/libemqtt/luat_mqtt_client.c

@@ -98,6 +98,11 @@ int luat_mqtt_set_rxbuff_size(luat_mqtt_ctrl_t *mqtt_ctrl, uint32_t rxbuff_size)
 	return 0;
 }
 
+int luat_mqtt_set_keepalive(luat_mqtt_ctrl_t *mqtt_ctrl, uint32_t keepalive){
+    mqtt_ctrl->keepalive = keepalive;
+    return 0;
+}
+
 int luat_mqtt_set_connopts(luat_mqtt_ctrl_t *mqtt_ctrl, luat_mqtt_connopts_t *opts) {
     memcpy(mqtt_ctrl->host, opts->host, strlen(opts->host) + 1);
     mqtt_ctrl->remote_port = opts->port;