Use NumPy max instead of amax

These are aliases of the same function but max is more commonly used and understood.

scripts/omGeoJSON.py

@@ -72,7 +72,7 @@ def processGeoJSON():
         # extract the meaningful dimensions from the NetCDF variables
         ds_slice[layer_name] = ds[layer_name][:][0][0]
         # find the max emission value in a single cell for each layer
-        max_values[layer_name] = np.amax(ds_slice[layer_name])
+        max_values[layer_name] = np.max(ds_slice[layer_name])
 
     # Add GeoJSON Polygon feature for each grid location
     features = []