The plugin should not support GeoNode 3 instances #326
Description
The latest release of the plugin supports only GeoNode 4. Currently, we applied several changes in order to support also GeoNode 5.
In these changes, we modifed the way where the plugin checks for the supported versions: #318
Instead of checking the version.txt file, it checks the validity of the /api/v2/ client's response.
However the last versions of GeoNode 3 (3.3.x), supports the /api/v2/, so we need to ensure that even in this case, GeoNode 3 instances are not supported.