Require Node.js 20 and update CI/docs

Bump the project's Node requirement to v20 and align tooling and docs. Updates package.json engines and Volta pin, .nvmrc, README, CONTRIBUTING, copilot-instructions.md, and the getting-started docs to require Node.js 20. Adjust CI workflows by adding concurrency groups to ossf-scorecard, spellcheck, and super-linter, and remove Node 18 from the test matrix so tests run on 20/22/24. These changes standardize the development environment on Node 20 LTS and reduce duplicated CI runs.

Author: coliff

.github/CONTRIBUTING.md

@@ -11,6 +11,10 @@ We welcome any type of contribution, not only code. You can help with
 - **Community**: presenting the project at meetups, organizing a dedicated meetup for the local community, ...
 - **Code**: take a look at the [open issues](https://github.com/HTMLHint/HTMLHint/issues). Even if you can't write code, commenting on them, showing that you care about a given issue matters. It helps us triage them.
 
+## Development setup
+
+Use Node.js 20 or later (the repo pins a version with [Volta](https://volta.sh/) in `package.json`).
+
 ## Submitting code
 
 Any code change should be submitted as a pull request. The description should explain what the code does and give steps to execute it. The pull request should also contain tests.

.github/copilot-instructions.md

@@ -6,7 +6,7 @@
 - All code should be formatted with Prettier.
 - Use ESLint to check for JavaScript errors.
 - Rollup is used for building the project.
-- Node v20 is used for development.
+- Node.js 20 or newer is required; Volta pins the repo to Node 20 LTS in `package.json`.
 - Core code is in TypeScript v5.4.5.
 - All new rules for HTMLHint should be placed in the rules directory.
 - Tests for new rules should be added in rules and follow the naming pattern `<rule-name>.spec.js`.

.github/workflows/ossf-scorecard.yml

@@ -7,6 +7,10 @@ on:
   push:
     branches: ['main']
 
+concurrency:
+  group: scorecard-${{ github.ref }}
+  cancel-in-progress: true
+
 permissions: read-all
 
 jobs:

.github/workflows/spellcheck.yml

@@ -6,6 +6,10 @@ on:
   pull_request:
     branches: [main]
 
+concurrency:
+  group: spellcheck-${{ github.ref }}
+  cancel-in-progress: true
+
 permissions:
   contents: read
 

.github/workflows/super-linter.yml

@@ -9,6 +9,10 @@ on:
     branches-ignore:
       - 'dependabot/**'
 
+concurrency:
+  group: super-linter-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 permissions:
   contents: read
 

.github/workflows/test.yml

@@ -43,7 +43,6 @@ jobs:
       fail-fast: false
       matrix:
         node:
-          - 18
           - 20
           - 22
           - 24

.nvmrc

@@ -1 +1 @@
-v20
+v20.20.1

README.md

@@ -38,6 +38,8 @@
 
 ## 📟 Installation and Usage
 
+HTMLHint requires [Node.js](https://nodejs.org/) 20 or later.
+
 There are two ways to install HTMLHint: globally and locally.
 
 ### Local Installation and Usage

package-lock.json

@@ -79,9 +79,9 @@
     "typescript": "5.4.5"
   },
   "engines": {
-    "node": ">=18"
+    "node": ">=20"
   },
   "volta": {
-    "node": "18.20.8"
+    "node": "20.20.1"
   }
 }