chore: fix xml, curl not declared in the require list of composer

Author: lihsai0

composer.json

@@ -19,6 +19,8 @@
     ],
     "require": {
         "php": ">=5.3.3",
+        "ext-xml": "*",
+        "ext-curl": "*",
         "myclabs/php-enum": "~1.5.2 || ~1.6.6 || ~1.7.7 || ~1.8.4"
     },
     "require-dev": {