Build: Update deps, modernize CI, migrate the ESLint config

Changes:
1. Update dependencies
2. Migrate to the ESLint flat config
3. Test on Node.js 24, not 16
4. Update actions
5. Enable dependabot updates
6. Fix lint issues

Author: mgol

.editorconfig

@@ -9,3 +9,7 @@ end_of_line = lf
 charset = utf-8
 trim_trailing_whitespace = true
 insert_final_newline = true
+
+[*.{json,yml}]
+indent_style = space
+indent_size = 2

.eslintignore

@@ -0,0 +1,13 @@
+version: 2
+updates:
+  - package-ecosystem: github-actions
+    directory: "/"
+    schedule:
+      interval: monthly
+
+    # Group all dependabot version update PRs into one
+    groups:
+      github-actions:
+        applies-to: version-updates
+        patterns:
+          - "*"

.eslintrc.json

@@ -1,35 +1,30 @@
 name: CI
 
-on: [push, pull_request]
+on:
+  pull_request:
+  push:
+    branches-ignore: "dependabot/**"
 
 jobs:
   build:
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:
-        NODE_VERSION: [16.x]
+        NODE_VERSION: [24.x]
     steps:
-    - name: Checkout
-      uses: actions/checkout@v2
+      - name: Checkout
+        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
 
-    - name: Cache
-      uses: actions/cache@v2
-      with:
-        path: ~/.npm
-        key: ${{ runner.os }}-node-${{ matrix.NODE_VERSION }}-npm-lock-${{ hashFiles('**/package-lock.json') }}
-        restore-keys: |
-          ${{ runner.os }}-node-${{ matrix.NODE_VERSION }}-npm-lock-
+      - name: Use Node.js ${{ matrix.NODE_VERSION }}
+        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
+        with:
+          node-version: ${{ matrix.NODE_VERSION }}
+          cache: npm
+          cache-dependency-path: '**/package-lock.json'
 
-    - name: Use Node.js ${{ matrix.NODE_VERSION }}
-      uses: actions/[email protected]
-      with:
-        node-version: ${{ matrix.NODE_VERSION }}
+      - name: Install dependencies
+        run: npm ci
 
-    - name: Install dependencies
-      run: |
-        npm install
-
-    - name: Run tests
-      run: |
-        npm test
+      - name: Run tests
+        run: npm test

.github/dependabot.yml

@@ -0,0 +1,39 @@
+import jqueryConfig from "eslint-config-jquery";
+import globals from "globals";
+
+export default [
+	{
+
+		// Only global ignores will bypass the parser
+		// and avoid JS parsing errors
+		// See https://github.com/eslint/eslint/discussions/17412
+		ignores: [
+			"__release/**"
+		]
+	},
+
+	jqueryConfig,
+
+	{
+		languageOptions: {
+			ecmaVersion: 2025,
+			sourceType: "script",
+
+			globals: {
+				...globals.node
+			}
+		},
+
+		rules: {
+			strict: [ "error", "global" ]
+		}
+	},
+
+	{
+		files: [ "*.mjs" ],
+
+		languageOptions: {
+			sourceType: "module"
+		}
+	}
+];

.github/workflows/node.js.yml

@@ -18,7 +18,7 @@ Release.define( {
 		[ "git", "npm", "curl" ].forEach( function( command ) {
 			try {
 				which.sync( command );
-			} catch ( e ) {
+			} catch {
 				Release.abort( "Missing required executable: " + command );
 			}
 		} );