docs/website: update for 2021.05-rc3

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

docs/website/news.html

@@ -9,6 +9,27 @@
 <h2>News</h2>
 <ul class="timeline">
 
+  <li class="timeline-inverted">
+    <div class="timeline-badge"><i class="glyphicon glyphicon-thumbs-up"></i></div>
+    <div class="timeline-panel">
+      <div class="timeline-heading">
+	<h4 class="timeline-title">2021.05-rc3 released</h4>
+	<p><small class="text-muted"><i class="glyphicon glyphicon-time"></i>31 May 2021</small></p>
+      </div>
+      <div class="timeline-body">
+        <p>2021.05-rc3 has been released with more cleanups and build fixes. See the
+	  <a href="http://git.buildroot.net/buildroot/plain/CHANGES?id=2021.05-rc3">CHANGES</a>
+	  file for details.</p>
+
+	<p>Head to the <a href="/downloads/">downloads page</a> to pick up the
+	  <a href="/downloads/buildroot-2021.05-rc3.tar.bz2">2021.05-rc3
+	  release candidate</a>, and report any problems found to the
+	  <a href="support.html">mailing list</a> or
+	  <a href="https://bugs.buildroot.org">bug tracker</a>.</p>
+      </div>
+    </div>
+  </li>
+
   <li>
     <div class="timeline-badge"><i class="glyphicon glyphicon-thumbs-up"></i></div>
     <div class="timeline-panel">