get
https://sandboxapi.legendtrading.com/v2/app/states
查询国家下州列表 (Retrieve State List by Country)
返回指定国家的所有州列表。若返回值的 prohibited 字段为 true，则表示禁止该州用户注册。
Retrieve a list of all states for a specified country. If the prohibited field is true, user registration from that state is restricted.