title: AWS sync to deploy only new or updated files to s3
body: <p>I've written a Github actions script that takes files from a folder <code>migrations</code> and uploads it to s3. The problem with this pipeline is that all other files in the directory also get updated. How can I go about only updating new or updated files?
  Here's the current script as it stands.</p>
  <pre><code>name: function-name
  on:
    push:
      branches:
        - dev
  jobs:
    deploy:
      runs-on: ubuntu-latest
      strategy:
        matrix:
          node-version: [10.x]
      steps:
        - uses: actions/checkout@master
        - name: Use Node.js ${{ matrix.node-version }}
          uses: actions/setup-node@v1
          with:
            node-version: ${{ matrix.node-version }}
        - name: Install Dependencies
          run: npm install
        - name: Configure AWS Credentials
          uses: aws-actions/configure-aws-credentials@v1
          with:
            aws-access-key-id: ${{ secrets.AWS_ACCESS_KEY_ID }}
            aws-secret-access-key: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
            aws-region: eu-central-1
        - name: Deploy file to s3
          run: aws s3 sync ./migration/ s3://s3_bucket
  </code></pre>