Adding Math Fibonacci bug fixing

src/main/java/FibonacciSeries/implementation/MathFibonacciCalculator.java

@@ -9,6 +9,6 @@ public class MathFibonacciCalculator implements IFibonacciCalculator {
         double item2 = (1 - Math.sqrt(5))/2;
         item1 = Math.pow(item1,number);
         item2 = Math.pow(item2,number);
-        return Math.round((item1 + item2)/Math.sqrt(5));
+        return Math.round((item1 - item2)/Math.sqrt(5));
     }
 }