DOC: point to latest stable docs

Author: tacaswell

versions.html

@@ -1,7 +1,7 @@
 Other versions are available:
 
 <ul>
-  <li><a href="/2.1.0/index.html">2.1.0</a> Latest stable version.</a></li>
+  <li><a href="/2.1.1/index.html">2.1.1</a> Latest stable version.</a></li>
   <li><a href="/devdocs/index.html">2.x</a> Latest git master (unstable)</a></li>
   <li><a href="/2.0.2/index.html">2.0.2</a> Previous stable version.</a></li>
   <li><a href="/1.5.3/index.html">1.5.3</a> Older stable version.</a></li>