Add 172.[16-31].*.1 scanning

[shaunco]

Awesome work!

It looks like the choice of IPs scanned at https://github.com/samyk/webscan/blob/main/beta.js#L166 is some mix of known default residential gateway IPs across 10.0.0.0/8 and 192.168.0.0/16 plus a wildcard scan of 192.168.*.1, but nothing for the 172.16.0.0/12 range. A similar wildcard for 172.[16-31].*.1 would probably catch quite a few in the 172.16.0.0/12 private address space.