Minor code style fixes

Author: george-zakharov

composer.json

@@ -13,6 +13,8 @@
     ],
     "minimum-stability": "dev",
     "require": {
-        "php": ">=7.0"
+        "php": ">=7.0",
+      "ext-dom": "*",
+      "ext-libxml": "*"
     }
 }