Add security contact info to renderer readme

src/Phug/Renderer/README.md

@@ -1,9 +1,9 @@
 
 Phug Renderer
-===========
+=============
 
 What is Phug Renderer?
---------------------
+----------------------
 
 The Phug renderer get pug string or a pug file then return a markup string.
 
@@ -26,3 +26,10 @@ $html = $renderer->render($pugInput);
 
 //$html is now a string of HTML or any other markup according to the formatter you choose (XML, xHTML, etc.)
 ```
+
+Security contact information
+----------------------------
+
+To report a security vulnerability, please use the
+[Tidelift security contact](https://tidelift.com/security).
+Tidelift will coordinate the fix and disclosure.