Replaced i18n.t w/ tpl in core/server/api/v3/utils/validators/input/setup.js (#13534)
Replaced i18n.t w/ tpl in core/server/api/v3/utils/validators/input/setup.js (#13534)

refs: TryGhost#13380

- The i18n package is deprecated. It is being replaced with the tpl package.
ErisDS/Ghost,e10/Ghost,janvt/Ghost,TryGhost/Ghost,ErisDS/Ghost,e10/Ghost,ErisDS/Ghost,TryGhost/Ghost,TryGhost/Ghost,janvt/Ghost