Update rollbar logo

Author: tomchristie

docs/index.md

@@ -74,7 +74,7 @@ continued development by **[signing up for a paid plan][funding]**.
     <li><a href="https://getsentry.com/welcome/" style="background-image: url(https://fund-rest-framework.s3.amazonaws.com/sentry130.png)">Sentry</a></li>
     <li><a href="https://getstream.io/try-the-api/?utm_source=drf&utm_medium=banner&utm_campaign=drf" style="background-image: url(https://fund-rest-framework.s3.amazonaws.com/stream-130.png)">Stream</a></li>
     <li><a href="https://hello.machinalis.co.uk/" style="background-image: url(https://fund-rest-framework.s3.amazonaws.com/Machinalis130.png)">Machinalis</a></li>
-    <li><a href="https://rollbar.com" style="background-image: url(https://fund-rest-framework.s3.amazonaws.com/rollbar.png)">Rollbar</a></li>
+    <li><a href="https://rollbar.com" style="background-image: url(https://fund-rest-framework.s3.amazonaws.com/rollbar2.png)">Rollbar</a></li>
 </ul>
 <div style="clear: both; padding-bottom: 20px;"></div>