add gold sponsors

Author: Rain Liu

index.html

@@ -146,6 +146,11 @@
         <p>
           <strong>Sponsored with 💖 by</strong><br><br>
         </p>
+        <p>
+          <strong>Gold Sponsors:</strong><br><br>
+          <a href="https://www.parity.io/" target="_blank"><img src="./res/parity.png" style="height:75px;" alt="Parity Technologies"></a>
+        </p>
+        <br>
         <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