fix!: drop support for ESLint older than 8

[voxpelli]

Fixes #233

Companion PR to #234

Opted to not specify any specific minimum minor version for some reason:

• Wasn't done in the old version ranges
• No clear candidate from Drop older ESLint versions from peerDependencies #233 (comment) – either one of >=8.23.0, >=8.56.0, ^8.57.0 would make sense – but would require needless bumps by users of eslint-utils
• Not clear that there are something in the code of eslint-utils that requires a newer version

I guess >=8.23.0 could make sense as that's where the new flat config format was introduced, https://eslint.org/blog/2022/08/eslint-v8.23.0-released/, any opinions?

[voxpelli]

@MichaelDeBoey How does the auto-release handle the merge of two PR:s like this and #234? Will there be a double bump in the major version?

[MichaelDeBoey]

We should update GitHub workflows as well

[voxpelli]

We should update GitHub workflows as well

True, any opinion on the change itself? Or response to my question? :)

[MichaelDeBoey]

@voxpelli To answer your question: you should create a separate branch (if it's called alpha or beta, you also release an alpha/beta release to NPM) and merge these PRs into that new branch

Once all breaking changes are done, you can merge the new branch into main and you'll only have 1 major release.

If you merge both PRs directly to main, it could be that you're release 2 major versions, depending on how quick you are

[MichaelDeBoey]

Superseded by #243