use amend to avoid configuration

.github/workflows/update.yml

@@ -1,13 +1,5 @@
 name: Update docs and demo
-on: 
-  push:
-    branches-ignore:
-      - 'dependabot/**'
-    paths-ignore:
-      - 'README.md'
-      - 'demo/snake.zip'
-      - 'demo/qr.png'
-  workflow_dispatch:
+on: [push, workflow_dispatch]
 permissions:
   contents: write
   pages: write
@@ -27,12 +19,8 @@ jobs:
         xxd -p snake.com | python3 docs/update.py
         qrencode -r snake.com -8 -o demo/qr.png
         zip demo/snake.zip snake.com
-        git config --global user.email "$GITHUB_REPOSITORY_OWNER_ID+$GITHUB_REPOSITORY_OWNER@users.noreply.github.com"
-        git config --global user.name "$GITHUB_REPOSITORY_OWNER"
-        git add .
-        git commit -m "${GITHUB_WORKFLOW,,}"
+        git commit -a --amend --no-edit
         git push
-    - uses: actions/configure-pages@v4
     - uses: actions/upload-pages-artifact@v3
       with:
         path: 'demo/'