Removed extension from configuration

With zend-view we can't change default template files extension.

Author: michalbundyra

src/ConfigProvider.php

@@ -38,7 +38,6 @@ public function getDependencies() : array
     public function getTemplates() : array
     {
         return [
-            'extension' => 'phtml',
             'paths' => [],
         ];
     }