Update the footer to link to the new release notes (issue #12970)

Author: ariya

_includes/community.html

@@ -1,7 +1,7 @@
 <div class="community">
   <h2>Community:</h2>
   <ul>
-    <li><a href="{{ site.url }}/release-2.0.html" class="link-release">Read the release notes</a></li>
+    <li><a href="{{ site.url }}/release-2.1.html" class="link-release">Read the release notes</a></li>
     <li><a href="https://groups.google.com/forum/#!forum/phantomjs" class="link-ml">Join the mailing list</a></li>
     <li><a href="https://github.com/ariya/phantomjs/issues" class="link-bugs">Report bugs</a></li>
   </ul>