title: Gitlab CI not caching
body: <p>I have the following gitlab ci yaml file:</p>
  
  <pre><code>image: steveedson/ci
  
  stages:
    - build
  
  cache:
    untracked: true
    key: "$CI_PROJECT_ID"
    paths:
      - node_modules/
      - _site/vendor/
      - .bundled/
      - .yarn
  
  build:
    stage: build
    script:
      - ls -l
      - yarn config set cache-folder .yarn
      - yarn install
      - ...
  </code></pre>
  
  <p>When my successful builds finish, they show:</p>
  
  <pre><code>Creating cache 1970478...
  Created cache
  </code></pre>
  
  <p>And when the next commit triggers a build, I get:</p>
  
  <pre><code>Checking cache for 1970478...
  Successfully extracted cache
  </code></pre>
  
  <p>But the <code>ls -l</code> in my first step doesn't show the cached directories. I've tried caching the cache key but this doesn't help.</p>
  
  <p>This is running on gitlab.com, not a private server.</p>