Update jar

[tommy-gilligan]

I'm getting an error on my CSS

error: CSS: "overflow": "clip" is not a "overflow" value.

This seems to be because vnu.jar is a bit stale. Updating it here.
Using the jar from https://github.com/validator/validator/pkgs/npm/vnu-jar
Not sure what steps I should take to update CHANGELOG.md etc.

[mattxwang]

We (at just-the-docs) also depend on this repository and would love to see this PR (or a similar one) get merged; anything I can do to help merge this in!

[ptmkenny]

Instead of committing a binary, why not set up a workflow that pulls in the binary from an official source, like the NPM release? That way it would be easier to keep this repo up-to-date.

[Croydon]

The last commit is 2 years old.

@svenkreiss Do you still have the motivation and resources to maintain this project?

[mattxwang]

I will say, there are a few forks - this one seems like it's the most actively maintained: https://github.com/Cyb3r-Jak3/html5validator (the author maintains a useful GitHub Action that consumes this repository). If you're using this repository directly, switching (or forking) could be the next move!

(maintaining open-source is hard - grateful for all that's happened with this project so far!)