update index.html and dep graph

Author: Rain Liu

index.html

@@ -142,7 +142,10 @@
         </table>
         <hr>
         <p>
-          <strong>Sponsored with 💖 by</strong><br>
+          <strong>Sponsored with 💖 by</strong><br><br>
+        </p>
+        <p>
+          <strong>Silver Sponsors:</strong><br>
           <a href="https://getstream.io/?utm_source=github.com/webrtc-rs/webrtc&utm_medium=github&utm_campaign=oss_sponsorship" target="_blank"><img
             src="https://stream-blog-v2.imgix.net/blog/wp-content/uploads/f7401112f41742c4e173c30d4f318cb8/stream_logo_white.png?w=350" alt="Stream Chat"></a>
         </p>