[ticket/12475] Load extension migrations on cli updater too

PHPBB3-12475

phpBB/phpbb/console/command/db/migrate.php

@@ -115,6 +115,7 @@ class migrate extends \phpbb\console\command\command
 		$migrations = $this->extension_manager
 			->get_finder()
             ->core_path('phpbb/db/migration/data/')
+            ->extension_directory('/migrations')
 			->get_classes();
 		$this->migrator->set_migrations($migrations);
 	}