Upgrade Travis CI testing against latest GDAL and PROJ releases (#853)
Upgrade Travis CI testing against latest GDAL and PROJ releases (#853)

* GDAL 3.0.2 -> 3.0.3
 * GDAL 2.4.3 -> 2.4.4
 * PROJ 6.2.1 -> 6.3.0
Toblerity/Fiona,rbuffat/Fiona,rbuffat/Fiona,Toblerity/Fiona