Update actions/upload-artifact action to v7

.forgejo/workflows/deploy-docs.yaml

@@ -67,7 +67,7 @@ jobs:
         run: |
           rsync -v -r --delete -e "ssh -i deploykey.priv -o 'UserKnownHostsFile ./known_hosts'" site/ infra-docs-deploy@public-web-static.hosts.hamburg.ccc.de:/var/www/infra-docs.hamburg.ccc.de/
 
-      - uses: actions/upload-artifact@v3
+      - uses: actions/upload-artifact@v7
         if: github.event_name == 'pull_request'
         with:
           name: docs-build