title: Newman report generation works locally but not from CI
body: <p>I have a GitLab CI job running a series of Postman requests using a custom environment. I'm using Newman to run them alongside the <a href="https://www.npmjs.com/package/newman-reporter-htmlextra" rel="nofollow noreferrer">newman-reporter-htmlextra</a> npm plugin to generate a test report.</p>
  
  <p>The job looks like the following:</p>
  
  <pre><code>postman-tests:
    stage: postman-tests
    image: 
      name: wojciechzurek/newman-ci
    before_script:
      - cd ci/tests/postman
      - npm install -g newman-reporter-htmlextra
    script:
      - newman run Non-regression_tests.postman_collection.json -e Tests.postman_environment.json \
        --reporters htmlextra --reporter-htmlextra-export newman-results.html
      - ls -la # Check report generation
    artifacts:
      when: always
      paths:
        - newman-results.html
    allow_failure: true
  </code></pre>
  
  <p>When I run newman on my mac (newman 4.5.0), the requests and associated tests run properly and the report is generated. However, the job fails and the report is not generated:</p>
  
  <pre><code> $ newman run Non-regression_tests.postman_collection.json -e Tests.postman_environment.json --reporters htmlextra --reporter-htmlextra-export newman-results.html --color
  
  Uploading artifacts...
  
  WARNING: newman-results.html: no matching files    
  ERROR: No files to upload                          
  ERROR: Job failed: exit code 1
  </code></pre>
  
  <p>It seems that the issue may be caused by the testing series in itself rather than the report generation, as the job fails even when I don't generate the report.</p>
  
  <p>I tried different runners: Docker with official newman images, SSH and shell over machines where I had installed newman (version 4.5.6) and the htmlextra reporter beforehand. All fail.<br>
     It's interesting to note that the tests series and report generation <strong>both succeed when run locally on the machines</strong> behind the SSH and shell runners, but they do fail when launched from GitLab CI.</p>
  
  <p>What did I forget/do wrong that prevents the test report generation from GitLab CI?</p>