Use new ESLint API

[ota-meshi]

This PR refactors to use the new API instead of the old ESLint API.

See https://eslint.org/blog/2023/09/preparing-custom-rules-eslint-v9/

They are also present in the minimum version we support.

[changeset-bot]

🦋 Changeset detected

Latest commit: 17de9c3

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
eslint-plugin-regexp	Patch

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[RunDevelopment]

Code looks good, but I'm a bit worried about updating eslint and @types/eslint. Wouldn't this enable us to use newer API functions than our minimum supported ESLint version? I'm not sure if this will be an issue, but ideally we could use TS to enforce our minimum supported ESLint version. What do you think?

[ota-meshi]

I think we should use eslint@8.44.0 as you say 👍
I made sure that eslint@8.44.0 and @types/eslint@8.44.0 are used in package-lock.json so that we can use eslint@8.44.0 in our tests.