We thought Katy Perry had gone for every hair color combination possible on earth, but, then, last night she went and found just one more. And if you're an ombré fan, you're going to want to send it love notes. For the premiere of Jeremy Scott: The People's Designer (which features her as one of his muses), she changed up her jet-black hue by lightening the ends to a much lighter honey brown shade. Sure, we've seen her with black hair and we know her hair is naturally blond but this combo is…