Include npm lint in GitHub Action CI script

[dondi]

In addition to running the test suite, running our lint checker will help us catch formatting issues on an on-going basis

[akaiap]

• Created a pull request with the new command npm lint
• Succesfuly pushed the commit and was able to see the build in GitHub Actions.
• Test failed! (meaning npm lint worked) due to formatting issues
• The job failed due to two errors in the setup-handlers.js file:

1. Line 117: Trailing spaces are not allowed.
2. Line 137: Missing semicolon.