Update indexStable.html

Playground/indexStable.html

@@ -416,7 +416,7 @@
                 <a target='_new' href="https://www.netlify.com/">Deployed by Netlify</a>
             </div>
             <div class='link'>
-                <a target='_new' href="http://www.html5gamedevs.com/forum/16-babylonjs/">Forum</a>
+                <a target='_new' href="https://forum.babylonjs.com/">Forum</a>
             </div>
             <div class='link'>
                 <a target='_new' href="https://www.babylonjs.com/sandbox">Sandbox</a>
@@ -473,4 +473,4 @@
     </script>
 </body>
 
-</html>
+</html>