Removed blue notice bar which prompts about New class based API

Author: abhaynikam

guides/_layouts/guide.html

@@ -18,17 +18,6 @@
     </p>
   </div>
 {% endif %}
-{% if page.class_based_api %}
-  <div class="class-based-header">
-    <p>
-      <strong>⚠ New Class-Based API ⚠</strong>
-    </p>
-    <p>
-      This describes a new API in <code>v1.8.0</code>.
-      Check the <a href="/schema/class_based_api">upgrade notes</a> for more info.
-    </p>
-  </div>
-{% endif %}
 {% if page.pro %}
   <div class="pro-header">
     <p>