CienResolverのテストを追加

app/MetadataResolver/CienResolver.php

@@ -25,7 +25,7 @@ class CienResolver extends MetadataResolver
     public function resolve(string $url): Metadata
     {
         $res = $this->client->get($url);
-        $metadata = $this->ogpResolver->parse($res->getBody());
+        $metadata = $this->ogpResolver->parse((string) $res->getBody());
 
         // 画像URLから有効期限の起点を拾う
         parse_str(parse_url($metadata->image, PHP_URL_QUERY), $params);