InsertDNSPrefetch with head attributes

Some time head will have attributes.
https://developers.facebook.com/docs/reference/opengraph/object-type/article/

```
         })->unique()->implode("\n");
 
         $replace = [
-            '#<head>(.*?)#' => "<head>\n{$dnsPrefetch}"
+            '#<head[^>]*>(.*?)#' => "<head>\n{$dnsPrefetch}"
         ];
 
         return $this->replace($replace, $buffer);
```