获取公网IP

地址：https://ipinfo.io/json

{
  "ip": "221.176.33.221",
  "city": "Guangzhou",
  "region": "Guangdong",
  "country": "CN",
  "loc": "23.1167,113.2500",
  "postal": "510470",
  "org": "AS56040 China Mobile communications corporation"
}