site/.github/workflows/main.yml

name: deploy
on: 
  push:
    branches:
      - master

jobs:
  build:
    name: build and deploy
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@master
    
    - name: install dependencies
      run:  npm install

    - name: build
      run:  node_modules/gatsby/dist/bin/gatsby.js build

    - name: copy file via ssh password
      uses: appleboy/scp-action@master
      with:
        host: ${{ secrets.HOST }}
        key: ${{ secrets.NPM_GITHUB_PRIVATE_KEY }}
        source: "public/*"
        target: "/home/webmaster/html/"
        overwrite: true