Use this action to build an eleventy site and push to gh-pages

eleventy_build.yml

name: Eleventy Build
on: [push]

jobs:
  build_deploy:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@master
      - name: Build using node.ks
        uses: actions/setup-node@v1
        with:
          node-version: '12.x'
      - run: npm install
      - run: npm run build --if-present
      - name: Deploy
        uses: peaceiris/actions-gh-pages@v1.1.0
        env:
          PUBLISH_DIR: _site 
          PUBLISH_BRANCH: gh-pages
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}