Change Model::getDateFormat() to public

Author: RemiCollin

src/Jenssegers/Mongodb/Eloquent/Model.php

@@ -101,7 +101,7 @@ protected function asDateTime($value)
     /**
      * @inheritdoc
      */
-    protected function getDateFormat()
+    public function getDateFormat()
     {
         return $this->dateFormat ?: 'Y-m-d H:i:s';
     }

tests/models/User.php

@@ -65,7 +65,7 @@ public function father()
         return $this->embedsOne('User');
     }
 
-    protected function getDateFormat()
+    public function getDateFormat()
     {
         return 'l jS \of F Y h:i:s A';
     }