use FileIO in the basemap.jl file

Author: asinghvi17

src/basemap.jl

@@ -16,6 +16,8 @@ You do still have to provide the extent and image size, but this is substantiall
 
 =#
 
+using Makie: FileIO
+
 """
     basemap(provider::TileProviders.Provider, bbox::Extent; size, res, min_zoom_level = 0, max_zoom_level = 16)::(xs, ys, img)
 """