Instances of `SharedStyle` and `ColorAsset` not recognizing library update
I have a Sketch plugin that programmatically updates a Sketch library with new names/values for `sharedLayerStyles` and `colors`. This works great except that when the library updates instances of those library assets are not updated.

What seems to be happening is that Sketch isn't marking `sharedLayerStyles` or `colors` as having been updated if the Sketch API modified it. Possibly because there is no GUI in the Sketch app that allows this?

I saw mention of a `changeIdentifier` property [here](https://github.com/seek-oss/html-sketchapp-cli/issues/18) however I'm not sure exactly how to use that since it doesn't seem to be included in the docs.