Update RomanToInteger.java

In case if lower case roman letters are supplied, we need to convert into single case(Upper case).

Conversions/RomanToInteger.java

@@ -29,6 +29,7 @@ public class RomanToInteger {
      */
     public static int romanToInt(String A) {
 
+        A = A.toUpperCase();
         char prev = ' ';
 
         int sum = 0;