Rosanne Cash, the eldest daughter of Johnny Cash, postponed a trio of concert dates due to an “unexpected medical emergency.” The country singer’s team announced the concerning news on Monday via Instagram, without giving specifics about the health scare. “Rosanne Cash must postpone her performances due to an unexpected medical emergency. She is recovering under her doctors’ supervision, who have recommended a temporary restriction on travel and performing,” the statement read. “The restriction is impacting her upcoming Wyoming and Montana shows. Rosanne deeply regrets the cancellation and looks forward to rescheduling appearances.” The…