Merge branch '6.4' into 7.2

* 6.4:
  Update end_to_end.rst

Author: javiereguiluz

Diff for: testing/end_to_end.rst

@@ -26,7 +26,7 @@ to install the needed dependencies:
 
 .. code-block:: terminal
 
-    $ composer require symfony/panther
+    $ composer require --dev symfony/panther
 
 .. include:: /components/require_autoload.rst.inc