Fix an issue with being able to update statuses

Author: richardfullmer

lib/Github/Api/Repository/Statuses.php

@@ -43,6 +43,6 @@ public function create($username, $repository, $sha, array $params = array())
             throw new MissingArgumentException('state');
         }
 
-        return $this->post('repos/'.urlencode($username).'/'.urlencode($repository).'/statuses'.urlencode($sha), $params);
+        return $this->post('repos/'.urlencode($username).'/'.urlencode($repository).'/statuses/'.urlencode($sha), $params);
     }
 }