Update actions/download-artifact action to v5

Author: renovate[bot]

.github/workflows/asciidoc.yml

@@ -47,7 +47,7 @@ jobs:
     environment: github-pages-branch
     steps:
       - name: Download documentation artifact into ./public
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v5
         with:
           name: docs-${{ github.sha }}
           path: public