Chore: Run tests on Node.js v14

[fisker]

Prerequisites checklist

• I have read the contributing guidelines.
• The team has reached consensus on the changes proposed in this pull request. If not, I understand that the evaluation process will begin with this pull request and won't be merged until the team has reached consensus.

What is the purpose of this pull request? (put an "X" next to an item)

[ ] Documentation update
[ ] Bug fix (template)
[ ] New rule (template)
[ ] Changes an existing rule (template)
[ ] Add autofixing to a rule
[ ] Add a CLI option
[ ] Add something to the core
[X] Other, please explain:

Run tests on Node.js v14

What changes did you make? (Give an overview)

Add Node.js v14, remove v13 , v12 on windows and macOS

Is there anything you'd like reviewers to focus on?

Not much

[nzakas]

I think we can probably just remove this entry as we still want to test 12.x and this would exclude it.

[fisker]

We already test 12.x on linux, don't you think 10 + 14 is enough for macOS and windows?

[fisker]

Hmm, sorry I though 10.x is tested, seems we only test 12 on windows before, make sense, I'll add 12.x

[mysticatea]

I have intended the job to test ESLint with multiple versions of Node.js on Linux and with the LTS Node.js on multiple platforms. Because of avoiding combination explosion. I should write a comment about my intention, sorry.

Therefore, I think we should test on Windows/Mac with the LTS 12.x.

[kaicataldo]

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