Fixed

Superseded by this fork: https://www.codewars.com/kumite/5d4da226feb62f00153941e3?sel=5fd58299148bfb0022a19ecc.

Note the "Solution setup" contains invalid Go code - look at how every solution modifies it.

"already approved some time ago"

Approved.

Not for this kata and it's specified what is valid here:

IPs should be considered valid if they consist of four octets, with values between 0 and 255, inclusive.