BLD: remove matplotlib master from 2.7 (#682)
BLD: remove matplotlib master from 2.7 (#682)

Matplotlib master no longer supports python 2
jorisvandenbossche/geopandas,jorisvandenbossche/geopandas,geopandas/geopandas,jorisvandenbossche/geopandas,jdmcbr/geopandas,ozak/geopandas,jdmcbr/geopandas,ozak/geopandas,geopandas/geopandas,geopandas/geopandas