Modify Rule#apply signature to include parent node (allows context-aware rules)

[jrehwaldt]

Add JsonNode parent to rules.

This is required in order to implement context-aware rules, e.g. such as gh-910.

Breaking change.

[jrehwaldt]

This also helps implementing gh-909 and fixing gh-906. I've also seen previous PRs requiring similar functionality (e.g. gh-622).

I am open to implement another approach if you are in favor of another solution.

[joelittlejohn]

I think you're right that it would be good to get this change added before 1.0.0 is released 👍

[jrehwaldt]

Another refinement would be to add a general Context argument instead, which could then be extended further in the future. Part of this would be this parent, or maybe the whole branch (parent->parent's parent->...). Just putting it out as suggestion. Not sure if this would be better.

Something along the lines of

interface Context {
	JsonNode parent()
	JsonNode current()
    // extensible in future
}

[jrehwaldt]

Thanks for considering and merging! :)