feat!: drop Node 12/17 support

[bmish]

Goal is to match upcoming ESLint v9 core Node version support:

https://github.com/eslint/eslint/blob/845c4f40274ccb3727c624db44c7a23aafa71318/package.json#L164

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[nzakas]

Can you combine this with #133 ?

[bmish]

Just to explain my motivation here, I submitted these as two changes:

1. Drop Node versions
2. Upgrade dependencies

Because:

• Dropping Node versions is considered a breaking change while upgrading dependencies afterward is just a non-breaking feature/enhancement. I consider it good practice to isolate breaking changes from subsequent changes enabled by the breaking changes (of which there could be many).
• Both of these changes are relevant to consumers and deserve to be mentioned in the changelog, and I think it's nice to give each their own bullet point (by way of a separate PR) instead of trying to cram multiple into one.

[bmish]

@nzakas if we're considering generator-eslint package.json changes breaking but not the plugin template package.json, then I can split this into two PRs (one for each package.json), so we can release non-breaking changes first.

[nzakas]

I don't think there's much benefit to releasing non-breaking changes first. This package gets under 500 downloads a week, and people use it once and forget it, so we're not at much risk of breaking people's experiences. I'd say let's just merge everything and release it.

[bmish]

Fair enough. Then I think we can merge everything and do a major release.