Fix: Undefined variable

Fixes #240.
```
$sm = $this->getServiceLocator();
         $client = $sm->get('EdpGithub\Client');
 
-        if (!json_decode($module) instanceof \stdClass) {
-            return false;
-        }
         $query = 'repo:' . $repo->owner->login . '/' . $repo->name . ' filename:Module.php "class Module"';
         $response = $client->getHttpClient()->request('search/code?q=' . $query);
         $result = json_decode($response->getbody(), true);
```

Works locally for me