Remove unused methods from RepositoryInterface

src/Composer/Repository/RepositoryInterface.php

@@ -17,8 +17,5 @@ namespace Composer\Repository;
  */
 interface RepositoryInterface extends \Countable
 {
-    static function supports($type, $name = '', $url = '');
-    static function create($type, $name = '', $url = '');
-
     function getPackages();
 }