fixed index check in set that was always valid

Author: George Bouroutzoglou

src/main/java/gr/geompokon/bitarray/BitArray.java

@@ -198,7 +198,7 @@ public Boolean get(int index) {
      */
     public Boolean set(int index, Boolean bit) {
         Objects.requireNonNull(bit);
-        ensureIndexInRange(0, elements - 1);
+        ensureIndexInRange(index, elements - 1);
         modCount++;
         // get bit indices
         int longIndex = getLongIndex(index);