chore: use npm over Yarn with the latest dependencies

.github/workflows/ci.yml

@@ -16,21 +16,22 @@ jobs:
         node-version: [20.x, 22.x, 24.x]
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
 
     - name: Use Node.js ${{ matrix.node-version }}
-      uses: actions/setup-node@v1
+      uses: actions/setup-node@v4
       with:
         node-version: ${{ matrix.node-version }}
+        cache: 'npm'
 
     - name: Install dependencies
-      run: yarn install
+      run: npm ci
 
     - name: Run linter and tests
       run: |
-        yarn lint
-        yarn test
-        yarn coverage
+        npm run lint
+        npm run test
+        npm run coverage
 
     - name: Send test coverage report to Coveralls
       uses: coverallsapp/github-action@master

README.md

@@ -74,12 +74,6 @@ Using npm:
 $ npm install extensible-custom-error
 ```
 
-Using Yarn:
-
-```bash
-$ yarn add extensible-custom-error
-```
-
 ## Usage
 
 ### Define custom errors

eslint.config.js

@@ -0,0 +1,20 @@
+const js = require('@eslint/js');
+const globals = require('globals');
+
+module.exports = [
+  js.configs.recommended,
+  {
+    languageOptions: {
+      globals: {
+        ...globals.node,
+        ...globals.mocha,
+      },
+    },
+  },
+  {
+    files: ['index.mjs'],
+    languageOptions: {
+      sourceType: 'module',
+    },
+  },
+];