Remove Opbeat sponsor link (#397)

Author: mathiasbynens

templates/partials/footer.hbs

@@ -4,7 +4,6 @@
     <ul>
       <li>
         <h4>Sponsors</h4>
-        <p>Supported by <a href="https://opbeat.com/">Opbeat</a></p>
         <p>Hosting generously provided by <a href="https://m.do.co/c/b426e15331e8">DigitalOcean</a> and <a href="https://zeit.co/">Zeit</a></p>
 
         <p><a href="/sponsor">Learn how to become a sponsor</a></p>