GitHub Actions 自动关闭 issue 为啥不生效？

我写了个 GitHub Actions 工作流，想在 push 到 main 分支时自动关闭带特定标签的 issue，但一直没反应。

试过用 github.event.label.name 判断标签，也检查了 token 权限，还是不行。这是我的 workflow 配置：

name: Close Issues
on:
  push:
    branches: [main]
jobs:
  close-issues:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/github-script@v6
        with:
          script: |
            const issues = await github.rest.issues.listForRepo({
              owner: context.repo.owner,
              repo: context.repo.repo,
              labels: 'stale'
            });
            for (const issue of issues.data) {
              await github.rest.issues.update({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: issue.number,
                state: 'closed'
              });
            }
          github-token: ${{ secrets.GITHUB_TOKEN }}