demo1.yml 解释

1、运行 在 main 分支上运行 yarn yarn build

2、将 build 文件夹的内容推送到当前仓库的 gh-pages 分支

name: Build and Deploy
on:
  push:
    branches:
      - main
jobs:
  build-deploy:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v2.3.1

      - name: Install and Build
        run: |
          yarn
          yarn build

      - name: Deploy
        uses: JamesIves/github-pages-deploy-action@4.1.1
        with:
          branch: gh-pages
          folder: build
          clean: true