Description of change

It collects coverage and uploads it to Coveralls.

A maintainer needs to configure the repo on the coveralls site, no other action is needed to make it work.

Needs to be squashed.

Pull-Request Checklist

• Code is up-to-date with the master branch
• npm run format to apply prettier formatting
• npm run test passes with this change
• This pull request links relevant issues as Fixes #0000
• There are new or updated unit tests validating the change
• Documentation has been updated to reflect this change
• The new commits follow conventions explained in CONTRIBUTING.md