Update Symfony bundle metadata

Author: javiereguiluz

.symfony.bundle.yaml

@@ -14,6 +14,11 @@ branches:
 maintained_branches:
     - "2.15.x"
     - "2.16.x"
-doc_dir: { "2.12.x": "docs/", "2.13.x": "docs/en/" }
+doc_dir:
+    "2.12.x": docs/
+    "2.13.x": docs/en/
+    "2.14.x": docs/en/
+    "2.15.x": docs/en/
+    "2.16.x": docs/en/
 current_branch: "2.15.x"
 dev_branch: "2.16.x"