upgrade mailgun-php

Author: andruha

Message.php

@@ -356,15 +356,15 @@ public function getTestMode()
     }
 
     /**
-     * @return Array message object
+     * @return array message object
      */
     public function getMessage()
     {
         return $this->getMessageBuilder()->getMessage();
     }
 
     /**
-     * @return Array files list
+     * @return array files list
      */
     public function getFiles()
     {

composer.json

@@ -16,7 +16,7 @@
     ],
     "require": {
         "yiisoft/yii2": "*",
-        "mailgun/mailgun-php": "1.8"
+        "mailgun/mailgun-php": "~2.1"
     },
     "autoload": {
         "psr-4": {