Between its sloping silhouette and stunning vistas, Red Rocks Amphitheatre hardly seems to change over the years. That’s true in some ways. But ever-evolving rules — did you know it was BYOB until 1997? — constant upgrades, and a carousel of new bookings tell another story. Most of us wouldn’t be expected to know every name on the venue’s 2024 calendar (which begins Saturday, March 30, with a show from Boogie T).