moved to google analytics 4

Author: rhornig

_config.yml

@@ -6,6 +6,7 @@ twitter_username: omnetpp
 github_username:  omnetpp
 excerpt_separator: <!--more-->
 google_analytics: UA-240922-2
+google_analytics4: G-QGGDS2R96M
 
 sass:
     style: compressed

_includes/google-analytics.html

@@ -6,6 +6,14 @@
 
   ga('create', '{{ site.google_analytics }}', 'auto');
   ga('send', 'pageview');
+<!-- Global site tag (gtag.js) - Google Analytics -->
+<script async src="https://www.googletagmanager.com/gtag/js?id=G-QGGDS2R96M"></script>
+<script>
+  window.dataLayer = window.dataLayer || [];
+  function gtag(){dataLayer.push(arguments);}
+  gtag('js', new Date());
 
+  gtag('config', '{{ site.google_analytics4 }}');
+</script>
 </script>