title: How to pull NPM dependency from private GitLab Git repo during GitLab CI build
body: <p>I have a job in my <code>.gitlab-ci.yml</code> file which does an <code>npm install</code> like so:</p>
  
  <pre><code>test:
    image: node:10
    script:
      - npm install
      - npm test
  </code></pre>
  
  <p>The problem is that I'm referencing a private GitLab repo in my <code>package.json</code>:</p>
  
  <pre><code>"dependencies": {
    "internal-dep": "git+https://gitlab.com/Company/internal-dep.git",
    ...
  </code></pre>
  
  <p>The <code>npm install</code> command works locally, since I'm already authed against GitLab, but fails on GitLab CI. How do I get <code>internal-dep</code> to resolve successfully on GitLab CI?</p>