DOC: add anonymizeIp for Google analytics in docs (pandas-dev#27662)

Author: jorisvandenbossche

doc/source/themes/nature_with_gtoc/layout.html

@@ -94,15 +94,15 @@ <h3 style="margin-top: 1.5em;">{{ _('Search') }}</h3>
     });
 });
 </script>
-<script type="text/javascript">
-  var _gaq = _gaq || [];
-  _gaq.push(['_setAccount', 'UA-27880019-2']);
-  _gaq.push(['_trackPageview']);
 
-  (function() {
-    var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;
-    ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
-    var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);
-  })();
+<!-- Google Analytics -->
+<script>
+window.ga=window.ga||function(){(ga.q=ga.q||[]).push(arguments)};ga.l=+new Date;
+ga('create', 'UA-27880019-2', 'auto');
+ga('set', 'anonymizeIp', true);
+ga('send', 'pageview');
 </script>
+<script async src='https://www.google-analytics.com/analytics.js'></script>
+<!-- End Google Analytics -->
+
 {% endblock %}