Add Traversable return type for getIterator

Author: Andrii Krasnoholovets

src/ObjectWrapper.php

@@ -10,6 +10,7 @@
 use ArrayAccess;
 use Paysera\Component\ObjectWrapper\Exception\InvalidItemTypeException;
 use Paysera\Component\ObjectWrapper\Exception\MissingItemException;
+use Traversable;
 
 class ObjectWrapper implements ArrayAccess, IteratorAggregate
 {
@@ -74,8 +75,7 @@ public function offsetUnset($offset): void
         throw new RuntimeException('Modifying ObjectWrapper is not allowed');
     }
 
-    #[\ReturnTypeWillChange]
-    public function getIterator()
+    public function getIterator(): Traversable
     {
         return new ArrayIterator($this->data);
     }