Ensure changes to withOptions plugins trigger rebuilds

src/util/createPlugin.js

@@ -15,6 +15,11 @@ createPlugin.withOptions = function(pluginFunction, configFunction = () => ({}))
 
  optionsFunction.__isOptionsFunction = true
 
+ // Expose plugin dependencies so that `object-hash` returns a different
+ // value if anything here changes, to ensure a rebuild is triggered.
+ optionsFunction.__pluginFunction = pluginFunction
+ optionsFunction.__configFunction = configFunction
+
  return optionsFunction
 }