🐛 returnn array of strings

The downstream version checking code expects an array of strings and the "github is unreachable"
default was returning a string.

airtime_mvc/application/models/Preference.php

@@ -912,7 +912,7 @@ class Application_Model_Preference
         self::setValue('latest_version', json_encode($latest));
         self::setValue('latest_version_nextcheck', strtotime('+1 week'));
         if (empty($latest)) {
-            return $config['airtime_version'];
+            return array($config['airtime_version']);
         } else {
             return $latest;
         }