表单验证：支持 IPV4、IPV6 带掩码2020-04-30Θ

# ipv4
10.255.101.19
# ipv4 with subnet
10.255.101.19/24
# invalid ipv4 with subnet
10.255.101.19/33
# ipv6
2408:8720:2000:10be:0:0:f:1
# ipv6 with subnet
2408:8720:2000:10be:0:0:f:1/64
# invalid ipv6 with subnet
2408:8720:2000:10be:0:0:f:1/129

var isCidr = require('is-cidr')
var isIp = require('is-ip')
const isIpOrSubnet = vip => isIp(vip) || isCidr(vip);