Update main.html to say no apps on PR's (#2623)

overrides/main.html

@@ -1,5 +1,12 @@
 {% extends "base.html" %}
 
+{% block header %}
+    {{ super() }}
+    <div style="color: red; text-align: center; padding: 10px; font-size: 20px;">
+        <strong>Announcement:</strong> We are currently not adding any applicatiosn to WinUtil and any apps that will be added through a PR will be declined by the maintainer.
+    </div>
+{% endblock %}
+
 {% block footer %}
     {# Empty block to override the footer #}
 {% endblock %}