[dxwg] Remove "maintainer" from dcat:Dataset usage note

jakubklimek has just created a new issue for https://github.com/w3c/dxwg:

== Remove "maintainer" from dcat:Dataset usage note ==
The usage note for ```dcat:Dataset``` states: ```In cases where a distinction between the actual dataset and its entry in the catalog is necessary (because metadata such as modification date and maintainer might differ), ...```. However, the word "maintainer" is not used anywhere else in the specification and therefore may cause confusion. I would remove this example or replace it with "listing date" which is actually present in the ```dcat:CatalogRecord``` description.


Please view or discuss this issue at https://github.com/w3c/dxwg/issues/203 using your GitHub account