Notification level for actual updates (or problems) only

[BenMcLean]

Is your feature request related to a problem? Please describe.

Currently, the notification levels are tied to log severity (info, warn, error), but many users want notifications based on whether updates actually occurred, regardless of log level.

Use case:

I want to be notified when containers are updated or when there are problems, but not when scans complete with no updates.

Current behavior:

WATCHTOWER_NOTIFICATIONS_LEVEL=info sends notifications for every scan, even when nothing changed
WATCHTOWER_NOTIFICATIONS_LEVEL=warn only sends notifications for warnings/errors, missing successful updates

Describe the solution you'd like

A new notification level like WATCHTOWER_NOTIFICATIONS_LEVEL=updates that would notify on:

• Successful updates (when Updated > 0)
• Warnings and errors

But skip notifications when Updated = 0 and no issues occurred

Describe alternatives you've considered

I currently get notifications on "warn" to stop the spam but it would be nice to get notified on actual updates.

Additional context

No response

[github-actions]

Hi there! 👋🏼 As you're new to this repo, we'd like to suggest that you read our code of conduct as well as our contribution guidelines. Thanks a bunch for opening your first issue! 🙏