[tacker] Wallaby vPTG

Hi team, I booked our slots, 27-29 Oct 6am-8am UTC, for the next vPTG[1] as we agreed in previous irc meeting. I also prepared an etherpad [2], so please add your name and suggestions. [1] https://ethercalc.openstack.org/7xp2pcbh1ncb [2] https://etherpad.opendev.org/p/Tacker-PTG-Wallaby Thanks, Yasufumi