[FrameworkBundle] Allow .yaml file extension everywhere

Author: ogizanagi

Dumper/YamlFileDumper.php

@@ -23,6 +23,13 @@
  */
 class YamlFileDumper extends FileDumper
 {
+    private $extension;
+
+    public function __construct(/**string */$extension = 'yml')
+    {
+        $this->extension = $extension;
+    }
+
     /**
      * {@inheritdoc}
      */
@@ -50,6 +57,6 @@ public function formatCatalogue(MessageCatalogue $messages, $domain, array $opti
      */
     protected function getExtension()
     {
-        return 'yml';
+        return $this->extension;
     }
 }