fix: add pnpm and node setup to dependabot workflow for merge driver

Co-authored-by: hotlong <50353452+hotlong@users.noreply.github.com>

Author: Copilot

.github/workflows/dependabot-auto-merge.yml

@@ -16,6 +16,17 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
 
+      - name: Setup pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 10
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20.x'
+          cache: 'pnpm'
+
       - name: Configure Git merge driver for pnpm-lock.yaml
         run: |
           # Configure custom merge driver for pnpm-lock.yaml