DOC: Add cf_xarray to ecosystem page (pydata#10443)

Author: VeckoTheGecko

doc/user-guide/ecosystem.rst

@@ -14,6 +14,7 @@ Geosciences
 
 - `aospy <https://aospy.readthedocs.io>`_: Automated analysis and management of gridded climate data.
 - `argopy <https://github.com/euroargodev/argopy>`_: xarray-based Argo data access, manipulation and visualisation for standard users as well as Argo experts.
+- `cf_xarray <https://cf-xarray.readthedocs.io/en/latest/>`_: Provides an accessor (DataArray.cf or Dataset.cf) that allows you to interpret Climate and Forecast metadata convention attributes present on xarray objects.
 - `climpred <https://climpred.readthedocs.io>`_: Analysis of ensemble forecast models for climate prediction.
 - `geocube <https://corteva.github.io/geocube>`_: Tool to convert geopandas vector data into rasterized xarray data.
 - `GeoWombat <https://github.com/jgrss/geowombat>`_: Utilities for analysis of remotely sensed and gridded raster data at scale (easily tame Landsat, Sentinel, Quickbird, and PlanetScope).