ci: simplify to single workflow with latest LTS Node.js

- Remove old markdown link checker workflow (action.yml)
- Simplify tests.yml to use only latest LTS Node.js
- Remove coverage step for simpler workflow

Author: leonardomso

.github/workflows/action.yml

@@ -10,26 +10,18 @@ jobs:
   test:
     runs-on: ubuntu-latest
 
-    strategy:
-      matrix:
-        node-version: [20.x, 22.x]
-
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
 
-      - name: Setup Node.js ${{ matrix.node-version }}
+      - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
-          node-version: ${{ matrix.node-version }}
+          node-version: 'lts/*'
           cache: 'npm'
 
       - name: Install dependencies
         run: npm ci
 
       - name: Run tests
         run: npm test
-
-      - name: Run tests with coverage
-        if: matrix.node-version == '20.x'
-        run: npm run test:coverage