Updated minimum version of py_tools_ds.

requirements.txt

 geoarray>=0.6.16
-py_tools_ds>=0.9.3
+py_tools_ds>=0.12.0
 cmocean
 numpy
 gdal

setup.py

@@ -14,7 +14,7 @@ with open('HISTORY.rst') as history_file:
     history = history_file.read()
 
 requirements = ['numpy', 'gdal', 'shapely', 'scikit-image', 'matplotlib', 'geopandas', 'geoarray>=0.6.16',
-                'py_tools_ds>=0.9.3', 'plotly', 'cmocean', 'six',
+                'py_tools_ds>=0.12.0', 'plotly', 'cmocean', 'six',
                 # 'pykrige'  # conda install --yes -c conda-forge pykrige
                 # 'pyfftw', # conda install --yes -c conda-forge pyfftw=0.10.4 ; \
                 # 'basemap', # conda install --yes -c conda-forge basemap; \