Cast document id to string as id in the Document class supports strin…

…g only

src/Index.php

@@ -297,7 +297,7 @@ public function getDocument($id, array $options = []): Document
                 $data = [];
             }
 
-            $doc = new Document($id, $data, $this->getName());
+            $doc = new Document((string) $id, $data, $this->getName());
             $doc->setVersionParams($result);
 
             return $doc;