message: [certification] return ipv6 in testharness-discovery script
  Current implementation returns on Windows platforms by default IPv4
  address and with this commit we will start to return IPv6 link local.
diff: @@ -53,7 +53,7 @@ def if_nametoindex(name):
  def get_ipaddr():
  - for line in os.popen(f'ip addr list dev {IFNAME} | grep inet | grep global'):
  + for line in os.popen(f'ip addr list dev {IFNAME} | grep inet6 | grep \'scope link\' '):
  addr = line.strip().split()[1]
  return addr.split('/')[0]
  