Add Esri World Dark Gray Canvas basemap about xyzservices

[EwoutH]

Thanks!

[darribas]

The link provided seems to be deprecated, this is the updated version:

https://www.arcgis.com/home/item.html?id=358ec1e175ea41c3bf5c68f0da11ae2b

This one however is a vector lile layer, so not currently supported by xyzservices (or contextily for that matter). If you're using it on Leaflet, you can use their recommended URL:

https://basemaps.arcgis.com/arcgis/rest/services/World_Basemap_v2/VectorTileServer/tile/{z}/{x}/{y}.pbf

Closing the issue for now as not supported, but we can reopen down the line if we manage to add support for vector tiles.