DOC: fix random state in geoplot voronoi example to prevent random errors (#933)
DOC: fix random state in geoplot voronoi example to prevent random errors (#933)

See ResidentMario/geoplot#69: depending on how the data are subsampled, we stumble into a potential bug in geoplot. So fixing the random state with a working one to prevent this.
jorisvandenbossche/geopandas,jorisvandenbossche/geopandas,jorisvandenbossche/geopandas,geopandas/geopandas,geopandas/geopandas,jdmcbr/geopandas,jdmcbr/geopandas,geopandas/geopandas