renovate
Renovate is running in a cron job in the swarm and scanning git repositories specified in the config.js in order to automatically submit pull requests for dependency upgrades. Renovate supports multiple languages and frameworks (see "Language support"). This helps us keep our Docker file tags and Compose versions update to date, amongst other things.
Configured according to this guide.
See autonomic-cooperative/swarm-cronjob for the swarm-based cron job configuration.