Maintenance status

Hi @lahmatiy,

I am one of the maintainers of Stylelint.

In Stylelint we use `csstree` to validate the values for each property.
The rule in question isn't part of a standard config but we are hoping it might be in the future.
We think that this kind of validation is really valuable for CSS authors.

This rule is very similar to https://github.com/csstree/stylelint-validator

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Since creating this rule we have encountered various false positives/negatives because the syntax data published with `csstree` is starting to fall behind.

We are unsure what the current status is of `csstree` and if regular updates might resume in the future?

Having a bit more insights into the status of `csstree` would help us pick a path forwards.

An equally valid path forwards would be for us to maintain our own dataset but we rather contribute here so that more people can benefit from these updates.

Thank you in advance