Update dedicated-domains.md
Update dedicated-domains.md

Removed reference to specific appliance version as no longer relevant. Modified MAY to MUST for webtasks on dedicated domain, as this is mandatory and no longer optional.
auth0/docs,yvonnewilson/docs,yvonnewilson/docs,yvonnewilson/docs,jeffreylees/docs,jeffreylees/docs,auth0/docs,auth0/docs,jeffreylees/docs