Fix #95 with NodeJS v. 20

[blaisep]

🤔 What's changed?

update project and test matrix to nodeJS v20

⚡️ What's your motivation?

Earn the respect of @olleolleolle and @mpkorstanje

🏷️ What kind of change is this?

• 🏦 Refactoring/debt/DX (improvement to code design, tooling, etc. without changing behaviour)
• 🐛 Bug fix (non-breaking change which fixes a defect)

♻️ Anything particular you want feedback on?

Should I bump a release?
Is v20 LTS the wrong choice?

📋 Checklist:

• I agree to respect and uphold the Cucumber Community Code of Conduct
• I've changed the behaviour of the code
  • I have added/updated tests to cover my changes.
• My change requires a change to the documentation.
  • I have updated the documentation accordingly.
• Users should know about my change
  • I have added an entry to the "Unreleased" section of the CHANGELOG, linking to this pull request.

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[blaisep]

Hi @mattwynne , this is failing because of some ts dependencies, I think.
https://github.com/cucumber/action-retire-inactive-contributors/actions/runs/13040580193/job/36381309456?pr=97
If this is obvious to you, please go ahead and fix it, otherwise I will ask @nhv96 to look at it since he's more familiar with NodeJS.

[mattwynne]

Hi Blaise,

The error from the build is:

> eslint . --ext .ts

Invalid option '--ext' - perhaps you meant '-c'?
You're using eslint.config.js, some command line flags are no longer available. Please see https://eslint.org/docs/latest/use/command-line-interface for details.

That's coming from this line

I suggest reading the docs as the error message points to, and see if you can figure out what the right command-line args for eslint are now. You can test the command on the branch with npm run lint.

Good luck!

[blaisep]

Sigh.
JavaScript never fails to disappoint. The subsequent error message says:

The ".eslintignore" file is no longer supported. Switch to using the "ignores" property in "eslint.config.js": https://eslint.org/docs/latest/use/configure/migration-guide#ignoring-files

Then, following the link to the docs, it says:

With eslintrc, you can make ESLint ignore files by creating a separate .eslintignore file in the root of your project. The .eslintignore file uses the same glob pattern syntax as .gitignore files. Alternatively, you can use an ignorePatterns property in your eslintrc file.

Makes no mention of a eslint.config.js and refers only to the (apparently deprecated) .eslintignore file.
I will ask @nhv96 for the best way to update this since he's my node guru.