build_and_deploy.yml

name: Build and Deploy
on: 
  push:
    branches: 
      - master
jobs:
  build-and-deploy:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v2.3.1 # If you're using actions/checkout@v2 you must set persist-credentials to false in most cases for the deployment to work correctly.
        with:
          persist-credentials: false

      - name: Install and Build
        run: |
          npm install
          npm run build
          cp ./build/index.html ./build/404.html

      - name: Deploy 
        uses: JamesIves/github-pages-deploy-action@3.7.1
        with:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          BRANCH: gh-pages # The branch the action should deploy to.
          FOLDER: build # The folder the action should deploy.
          CLEAN: true # Automatically remove deleted files from the deploy branch\