Given a string, reverse its order, change lowercase letters to uppercase and increment uppercase letters by one (e.g. A becomes B, C becomes D, Z becomes A).
change_string("ApPle") ➞ "ELQPB"
change_string("draGON") ➞ "OPHARD"
change_string("ZebrA") ➞ "BRBEA"
Remember capital "Z" becomes "A".