Monitor remaining heroku hours

[grimord]

Once the integration project is deployed onto Heroku:

Create monitoring workflow to keep track of remaining monthly free Heroku hours and generate alert notifications if some to-be-defined lower threshold is reached.

This amount can be obtained through the heroku cli heroku ps -a <app-name> (which is pre-installed on Ubuntu runner VMs as of today)

Consider logging and persisting this information somewhere for tracking / analysis?