chore: Add final function in RockPaperScissors class to pass Checkstyle

Author: ligiastalves

src/main/java/com/thealgorithms/puzzlesandgames/RockPaperScissors.java

@@ -17,7 +17,7 @@
  * Result: You win!
  * Author: Lígia Alves (Hacktoberfest 2025)
  */
-public class RockPaperScissors {
+public final class RockPaperScissors {
 
     private RockPaperScissors() {
         throw new UnsupportedOperationException("Utility class");