Fix API deprecations blocking eslint v9 compatibility

[LucasHill]

There are a couple deprecations in eslint that are preventing this plugin from working under v9. As this addon already supports the flat config format, I believe these should be the only changes needed to work under v9.

currentSegments deprecation: eslint/eslint#17457
'context.getAncestors` deprecation: https://eslint.org/blog/2023/09/preparing-custom-rules-eslint-v9/#context.getancestors()

This was my reference for how to fix this rule: https://github.com/eslint/eslint/blob/main/lib/rules/getter-return.js

[LucasHill]

I may have been a little too confident. I'm finding a few more deprecations. What the current work does do is unblock using the eslint/compat tool for this plugin to work under v9. I'll see how extensive the remaining issues are, but this is mergeable as is or I can try to fix the rest.

[NullVoxPopuli]

thank you!