Make new inner class final

Author: garydgregory

src/main/java/org/apache/commons/collections4/bloomfilter/IndexExtractor.java

@@ -103,7 +103,7 @@ public boolean processIndices(final IntPredicate predicate) {
      * @return An int array of the data.
      */
     default int[] asIndexArray() {
-        class Indices {
+        final class Indices {
             private int[] data = new int[32];
             private int size;