Update GTM ID (#57)

Author: mango-db

src/html/_layout.html

@@ -41,7 +41,7 @@
     <script src="js/landing.min.js"></script>
 
     <!-- Google Tag Manager -->
-    <noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-JQHP"
+    <noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-GDFN"
                       height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
     <script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push(
        {'gtm.start': new Date().getTime(),event:'gtm.js'}