Since we use `npm test` in CI and use a separate command for integration
tests, we need to make sure `npm test` runs the unit tests.

Will do linting and testing against each Node version and eslint version

Node v16 is out of support. So we test against Node v18 and v20.

eslint 7 was released 4 years ago so its fair to not actively test again
eslint 6. Speculativiely adding eslint 9 tests but not sure if that will
work

Also fix testing of multiple eslint versions

We weren't doing custom installations of different eslint versions
so we were always only testing one eslint version!

Added eslint-v9 test directory but it fails right now so not adding it
to CI.

This does a general update of package-lock.json files and also updates mocha everywhere. This helps remove some of the warnings when installing node modules.

eslint v9 made schema mandatory for options supported
by rules:
https://eslint.org/docs/latest/extend/custom-rules#options-schemas

Previously we didn't use the meta object on the rules
so now we create the meta object and populate the `schema` property.

Thanks to @BePo65 for providing context, docs and the schema itself.

- Updated .npmignore to not include `vendor` since its only needed for
  testing
- Added an explicit comment in the README to use v4 for newer eslints
- Updated package version
- Fixed git URL via `npm pkg fix`
- Bumped up node support version to the last supported LTS