title: How can I use private docker image in github actions
body: <p>I'm trying to set up a job in github-actions that runs a private docker image. I will do the build inside that docker image using the container option. <a href="https://docs.github.com/en/actions/reference/workflow-syntax-for-github-actions#jobsjob_idcontainer" rel="noreferrer">link</a>.</p>
  <p>I'm using the following code:</p>
  <pre><code>jobs:
    container1:
      runs-on: ubuntu-latest
      container: saeed/privateimage:1
      steps:
        - uses: actions/checkout@v2
        - run: |
            echo &quot;Runs inside a container&quot;
  </code></pre>
  <p>But I can't provide my docker hub creds so it fails.</p>
  <p>How can I authenticate to pull that private image?</p>
  <p>Thanks.</p>