New owslib version has a constructor which allows building csw client for version 2.0.2 and version 3.0.0. As the csw_client is directly inherited from the old owslib csw client, this just maintains the old functionality without supporting version 3.0.0.
Fixes #310
New owslib version has a constructor which allows building csw client for version 2.0.2 and version 3.0.0. As the csw_client is directly inherited from the old owslib csw client, this just maintains the old functionality without supporting version 3.0.0.