Change package-private constructor to private

Author: garydgregory

src/main/java/org/apache/commons/io/function/IOIteratorAdapter.java

@@ -34,7 +34,7 @@ static <E> IOIteratorAdapter<E> adapt(final Iterator<E> delegate) {
 
     private final Iterator<E> delegate;
 
-    IOIteratorAdapter(final Iterator<E> delegate) {
+    private IOIteratorAdapter(final Iterator<E> delegate) {
         this.delegate = Objects.requireNonNull(delegate, "delegate");
     }