feat(docs): Add analytics code to landing page

docs/layouts/index.en.html

@@ -134,6 +134,7 @@ $ yarn add @vendure/core@alpha</code>
     </div>
 </div>
 {{ partial "footer" }}
+{{ template "_internal/google_analytics_async.html" . }}
 <script src="{{ "intro.js" | relURL }}"></script>
 </body>
 </html>