Added 'known issue' of not supporting IPv6
Added 'known issue' of not supporting IPv6

aashley/teleport,yacloud-io/teleport,suedadam/teleport,ajvb/teleport,gravitational/teleport,bshelton229/teleport,sokoow/teleport,gravitational/teleport,yacloud-io/teleport,suedadam/teleport,gravitational/teleport,bshelton229/teleport,tidalf/teleport,aashley/teleport,aashley/teleport,aashley/teleport,yacloud-io/teleport,gravitational/teleport,suedadam/teleport,gravitational/teleport,yacloud-io/teleport,sokoow/teleport,bshelton229/teleport,sokoow/teleport,tidalf/teleport,suedadam/teleport,ajvb/teleport,tidalf/teleport,suedadam/teleport,sokoow/teleport,ajvb/teleport,tidalf/teleport,sokoow/teleport,bshelton229/teleport,ajvb/teleport,yacloud-io/teleport,yacloud-io/teleport,sokoow/teleport,tidalf/teleport,aashley/teleport,ajvb/teleport,bshelton229/teleport,gravitational/teleport,yacloud-io/teleport