GA4 추가 (#452)

Author: 9bow

_templates/layout.html

@@ -40,12 +40,13 @@
   }
 </script>
 
-<script async src="https://www.googletagmanager.com/gtag/js?id=UA-71919972-3"></script>
+<script async src="https://www.googletagmanager.com/gtag/js?id=G-E8MF0BRFZ6"></script>
 <script>
   window.dataLayer = window.dataLayer || [];
   function gtag(){dataLayer.push(arguments);}
   gtag('js', new Date());
-  gtag('config', 'UA-71919972-3');
+  gtag('config', 'G-E8MF0BRFZ6');   // GA4
+  gtag('config', 'UA-71919972-3');  // UA
 </script>