create StreamFactoryInterface

src/Potter/Stream/StreamFactoryInterface.php

@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Potter\Stream;
+
+use \Psr\Http\Message\StreamFactoryInterface as BaseStreamFactoryInterface;
+
+interface StreamFactoryInterface extends BaseStreamFactoryInterface
+{ }