Update admin.php
Update admin.php

add a note on our staged roll-out.
michaelletzgus/nextcloud-server,andreas-p/nextcloud-server,michaelletzgus/nextcloud-server,andreas-p/nextcloud-server,andreas-p/nextcloud-server,nextcloud/server,andreas-p/nextcloud-server,andreas-p/nextcloud-server,michaelletzgus/nextcloud-server,nextcloud/server,nextcloud/server,nextcloud/server,michaelletzgus/nextcloud-server