ci: use Node 20 for package tests

.github/workflows/ci.yml

@@ -12,34 +12,19 @@ permissions:
 jobs:
   test:
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        node-version: [20.x, 24.x]
 
     steps:
       - name: Checkout code
         uses: actions/checkout@v5
 
-      - name: Setup Node.js ${{ matrix.node-version }}
+      - name: Setup Node.js 20.x
         uses: actions/setup-node@v5
         with:
-          node-version: ${{ matrix.node-version }}
+          node-version: 20.x
           cache: npm
 
       - name: Install dependencies
         run: npm ci
 
       - name: Run tests with coverage
         run: npm run test:coverage
-
-      - name: Upload coverage to Codecov
-        if: matrix.node-version == '24.x'
-        uses: codecov/codecov-action@v5
-        continue-on-error: true
-        with:
-          token: ${{ secrets.CODECOV_TOKEN }}
-          files: ./coverage/lcov.info
-          fail_ci_if_error: false
-          verbose: true
-        env:
-          CODECOV_GPG_VERIFY: false