🧹 Versioning: Bump minimum Node.js version from 14.0.0 to 18.18.0

[JoshuaKGoldberg]

Overview

We're gearing up for a new major version of Mocha 11. That means we can bump the minimum Node engine version! Hooray! This is great for a couple of reasons:

• It unblocks bumping old package versions, i.e. 🚀 Feature: Update glob from 8.1.0 which is no longer supported #5148
• It means we can use newer JavaScript + platform features

We'd like to bump to, at the most strict, Node LTS. An added pressure is that Mocha is still used by large projects such as ESLint and TypeScript, which have older version support requirements.

Our current thought is to go with:

• Node LTS at time of v11 release: should all be supported
• 🚀 Feature: Update glob from 8.1.0 which is no longer supported #5148: whatever is needed for a reasonably recent glob version
• If a major consumer such as ESLint requires a slight extension of support range for its devDependencies, we could allow that too