Add missing google analytics client id

Author: versx

src/views/header.mustache

@@ -29,6 +29,7 @@
     <script type="text/javascript" src="https://cdn.jsdelivr.net/npm/leaflet.locatecontrol@v0.70.0/dist/L.Control.Locate.min.js" charset="utf-8"></script>
     {{#google_analytics_id}}
         <script type="text/javascript" src="//google-analytics.com/analytics.js"></script>
+        <script async src="https://www.googletagmanager.com/gtag/js?id={{google_analytics_id}}"></script>
     {{/google_analytics_id}}
     {{#google_adsense_id}}
         <script async type="text/javascript" src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js?client={{google_adsense_id}}" crossorigin="anonymous"></script>