Update Google Analytics snippet (#107)

Author: brsoff

_includes/analytics.html

@@ -1,7 +1,10 @@
-<script async src="https://www.googletagmanager.com/gtag/js?id=UA-90545585-1"></script>
 <script>
-  window.dataLayer = window.dataLayer || [];
-  function gtag(){dataLayer.push(arguments);}
-  gtag('js', new Date());
-  gtag('config', 'UA‌-90545585-1');
+  (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','https://www.google-analytics.com/analytics.js','ga');
+
+  ga('create', 'UA‌-90545585-1', 'auto');
+  ga('send', 'pageview');
+
 </script>