Use download-artifact v4

Author: lambdamoses

.github/workflows/deploy_bookdown.yml

@@ -38,7 +38,7 @@ jobs:
      - name: Checkout
        uses: actions/checkout@main
      - name: Download artifact
-       uses: actions/download-artifact@v1.0.0
+       uses: actions/download-artifact@v4
        with:
          # Artifact name
          name: _book # optional