Breaking: support new regex d flag (fixes #14640)

[ota-meshi]

WIP

Remaining steps:

• release espree.
• release regexpp.
• update package.json with the new versions of espree.
• update package.json with the new versions of regexpp.
• Fix test cases that failed due to upgrading espree.

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Fixes #14640.

Prerequisites checklist

• I have read the contributing guidelines.

What is the purpose of this pull request? (put an "X" next to an item)

[ ] Documentation update
[ ] Bug fix (template)
[ ] New rule (template)
[x] Changes an existing rule (template)
[ ] Add autofixing to a rule
[ ] Add a CLI option
[ ] Add something to the core
[x] Other, please explain: Upgrade the espree and the regexpp.

What changes did you make? (Give an overview)

This PR adds support for ES2022 RegExp Match Indices. Specifically, change the no-empty-character-class rule and no-invalid-regexp rule to allow the regex d flag.
https://github.com/tc39/proposal-regexp-match-indices

Is there anything you'd like reviewers to focus on?

I changed the no-empty-character-class rule to accept any flags.

[mdjermanovic]

LGTM once espree v8.0.0 is released and package.json updated.

Thanks for updating regexpp with the new syntax, and thanks for refactoring no-empty-character-class in a way that it doesn't have to be updated with new flags in the future.

[ota-meshi]

It seems that some existing rule tests fail due to upgrading espree to v8.x.
Will this issue be fixed in #14591? Or do you need another PR?

[mdjermanovic]

camelcase, id-denylist, id-blacklist, id-match, id-length are planned to be fixed in #14591, SourceCode#getComments() in #14748.

I think this PR can be marked as Ready for review (i.e. not draft) although the CI is failing. Once we fix the errors on master branch, we could re-run CI checks here.

[mdjermanovic]

LGTM, thanks!