fix: resolve PNPM version conflict in GitHub Actions workflow

- Update PNPM version specification to resolve build failures
- Ensure consistent PNPM version across CI/CD pipeline

Author: d-oit

.github/workflows/reusable-hugo-workflow.yml

@@ -26,6 +26,8 @@ jobs:
 
       - name: Install pnpm
         uses: pnpm/action-setup@v4
+        with:
+          version: pnpm
 
       - name: Set up Node.js
         uses: actions/setup-node@v4