Add PHP 8.1 support by specifying return types for getIterator and count (#1142)

* Test on PHP 8.1

* Specify return types for `getIterator` and `count`

This is required for PHP 8.1.

Author: ruudk

Model/AddressCollection.php

@@ -16,6 +16,7 @@
 use Geocoder\Exception\CollectionIsEmpty;
 use Geocoder\Exception\OutOfBounds;
 use Geocoder\Location;
+use Traversable;
 
 final class AddressCollection implements Collection
 {
@@ -35,15 +36,15 @@ public function __construct(array $locations = [])
     /**
      * {@inheritdoc}
      */
-    public function getIterator()
+    public function getIterator(): Traversable
     {
         return new \ArrayIterator($this->all());
     }
 
     /**
      * {@inheritdoc}
      */
-    public function count()
+    public function count(): int
     {
         return count($this->locations);
     }

Model/AdminLevelCollection.php

@@ -15,6 +15,7 @@
 use Geocoder\Exception\CollectionIsEmpty;
 use Geocoder\Exception\InvalidArgument;
 use Geocoder\Exception\OutOfBounds;
+use Traversable;
 
 /**
  * @author Giorgio Premi <giosh94mhz@gmail.com>
@@ -53,15 +54,15 @@ public function __construct(array $adminLevels = [])
     /**
      * {@inheritdoc}
      */
-    public function getIterator()
+    public function getIterator(): Traversable
     {
         return new \ArrayIterator($this->all());
     }
 
     /**
      * {@inheritdoc}
      */
-    public function count()
+    public function count(): int
     {
         return count($this->adminLevels);
     }