Read about the updated nuts package and gisco_get_*() functions

[lindadelacombaz]

Refers to @maurolepore's slack comment. NUTS3 data of several countries could be accessible from the function directly, without the need of having the nuts3 data locally (which we are doing now under /data-raw) + would be updated more easily for the recent years. Also, it seems that I have an issue with giscoR package. See my latest PR check that fails. Read the documentation and adapt the code accordingly:

• nuts package
• get_eurostat_geospatial()
• gisco_get_nuts()
• giscoR package

[maurolepore]

@lindadelacombaz I suspect you intended to open this issue in tiltPlot? I'll move it there.