🛠 Repo: Update Netlify Node version from 16 to a supported one

[JoshuaKGoldberg]

Tooling Suggestion Checklist

• I have tried restarting my IDE and the issue persists.
• I have pulled the latest master branch of the repository.
• I have read and agree to Mocha's Code of Conduct and Contributing Guidelines
• I have searched for related issues and issues with the faq label, but none matched my issue.
• I want to provide a PR to resolve this

Overview

mocha/netlify.toml

Line 17 in 9fbf3ae

NODE_VERSION = "16"

It'd be great if we could move to the latest even Node version, 20. Let's try for that.

Additional Info

Assigning to myself as an arbitrary Mocha team member.

[voxpelli]

@JoshuaKGoldberg Do we still need this when the new site is ready?

[JoshuaKGoldberg]

👍 we won't

mocha/docs-next/netlify.toml

Line 7 in 18699a0

NODE_VERSION = "20"