Switch to use of gtag.js library for analytics (#2207)

Signed-off-by: Patrice Chalin <[email protected]>

Signed-off-by: Patrice Chalin <[email protected]>

Author: chalin

layouts/footer.html

@@ -6,15 +6,14 @@
     <script src="/assets/docs.js"></script>
     <!-- IE10 viewport hack for Surface/desktop Windows 8 bug -->
     <script src="/assets/ie10-viewport-bug-workaround.js"></script>
-    <!-- Google Analytics -->
+    <!-- Global site tag (gtag.js) - Google Analytics -->
+    <script async src="https://www.googletagmanager.com/gtag/js?id=UA-58468480-1"></script>
     <script>
-      (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
-      (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
-      m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
-      })(window,document,'script','//www.google-analytics.com/analytics.js','ga');
+      window.dataLayer = window.dataLayer || [];
+      function gtag(){dataLayer.push(arguments);}
+      gtag('js', new Date());
 
-      ga('create', 'UA-58468480-1', 'auto');
-      ga('send', 'pageview');
+      gtag('config', 'UA-58468480-1');
     </script>
 
     <!-- Algolia Docsearch -->