Replace deprecated frameborder attribute with CSS border: 0

Co-authored-by: garrytrinder <11563347+garrytrinder@users.noreply.github.com>

Author: Copilot

src/pages/index.astro

@@ -258,8 +258,7 @@ import Layout from '../layouts/Layout.astro';
           <iframe
             src="https://www.youtube-nocookie.com/embed/HVTJlGSxhcw"
             title="Get started with Dev Proxy"
-            style="position: absolute; top: 0; left: 0; width: 100%; height: 100%;"
-            frameborder="0"
+            style="position: absolute; top: 0; left: 0; width: 100%; height: 100%; border: 0;"
             allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture"
             allowfullscreen
           ></iframe>