Update default.html

Author: chatgpt-helper-tech

docs/_layouts/default.html

@@ -12,6 +12,7 @@
     {% seo title=false %}
 
   <link rel="stylesheet" href="{{ '/assets/css/style.css' | relative_url }}">
+  <link rel="canonical" href="https://gptvpnhelper.com/chatgpt-plus-guide/" />
   <!-- Google tag (gtag.js) -->
 {% if site.google_analytics %}
 <script async src="https://www.googletagmanager.com/gtag/js?id={{ site.google_analytics }}"></script>