chore: try another branch to fix deployment

.github/workflows/deploy-v4-site.yml

@@ -59,11 +59,13 @@ jobs:
       - name: Deploy for GitHub 🚀
         uses: JamesIves/github-pages-deploy-action@v4.6.0
         with:
-          branch: main
+          branch: gh-pages
           folder: packages/vant/site-dist
           token: ${{ secrets.VANT_UI_TOKEN }}
           repository-name: vant-ui/vant-ui.github.io
           target-folder: vant
+          # enable single-commit to reduce the repo size
+          single-commit: true
           clean: true
           clean-exclude: |
             1.x/*