POST
/v1/email-captcha
required邮箱地址
required可选值为0或1，当验证码用于重置密码时，此字段置为1，当验证码用于注册时，此字段置为0。
{
"code": 0,
"data": null,
"msg": "发送成功!"
}{
"email": "xxx@qq.com",
"check_exist": 1
}{
"code": 0,
"data": null,
"msg": "发送成功!"
}{
"email": "xxx@qq.com",
"check_exist": 1
}