Document version parameter

lib/cartopy/feature/__init__.py

@@ -230,7 +230,9 @@ class NaturalEarthFeature(Feature):
     """
     A simple interface to Natural Earth shapefiles.
 
-    See https://www.naturalearthdata.com/
+    See https://www.naturalearthdata.com/ for an overview of the data
+    and https://github.com/nvkelso/natural-earth-vector/releases for recent
+    version information.
 
     """
 
@@ -246,6 +248,8 @@ def __init__(self, category, name, scale, version=None, **kwargs):
             The dataset scale, i.e. one of '10m', '50m', or '110m',
             or Scaler object. Dataset scales correspond to 1:10,000,000,
             1:50,000,000, and 1:110,000,000 respectively.
+        version: optional
+            The specific dataset version to use, e.g. '5.1.0'.
 
         Other Parameters
         ----------------