For five seasons, including the ambitious and acclaimed Crisis on Infinite Earths crossover storyline, Supergirl has given us Greg Berlanti-produced CW superhero action of the highest order, bolstered by a titular performance from Melissa Benoist. Fans have been wondering when we'll get a sixth season, and well, we've got some good news and some bad news. Per Variety, Supergirl's sixth season will air sometime in 2021 — and it will be the show's last season. [caption id="attachment_745642" align="alignright" width="360"] Image via The CW[/caption] The CW, Warner Bros. Television, and Berlanti Productions all …