Example from https://github.com/rubenafo/google-pinger for keeping URLs awake.
Replacing cron.xml to cron.yml as cron.xml is deprecated.
Since the sunset of Red Hat's Openshift Online Version 2, Heroku Free Dyno was chosen.
- https://cloud.google.com/appengine/docs/standard/java/config/cronref-yaml
- https://devcenter.heroku.com/articles/free-dyno-hours#dyno-sleeping