Add [DockerLastUpdated] badge for newest image date

[KesleyDavid]

Description

Adds a Docker Hub last updated badge that shows when the newest image tag (or a specific tag) was last pushed.

• Newest tag: /docker/last-updated/:user/:repo
• Specific tag: /docker/last-updated/:user/:repo/:tag
• Uses the public Docker Hub tags API with ordering=last_updated (same family as existing Docker badges)
• Renders via renderDateBadge (activity color scale by age)

Examples:

• https://img.shields.io/docker/last-updated/_/alpine
• https://img.shields.io/docker/last-updated/_/alpine/latest
• https://img.shields.io/docker/last-updated/datadog/dogstatsd

Live API verification

GET https://registry.hub.docker.com/v2/repositories/library/alpine/tags?page_size=1&ordering=last_updated
→ 200, results[0].last_updated present

GET https://registry.hub.docker.com/v2/repositories/library/alpine/tags/latest
→ 200, last_updated present

Tests

• Unit: npm run test:core -- --grep DockerLastUpdated → 4 passing
• Live service: npm run test:services -- --only=DockerLastUpdated → 6 passing
• Prettier + ESLint via pre-commit hook

References

• Closes Badge request: Newest dockerhub image #6016

AI note

Drafted with AI assistance; API responses, service pattern, and tests were verified locally before submitting.

[github-actions]

	Messages
📖	✨ Thanks for your contribution to Shields, @KesleyDavid!

Generated by 🚫 dangerJS against 2df0136

[PyvesB]

Love this example 🐶

[PyvesB]

Wouldn't "repository not found" be triggered by a 404? Couldn't this case instead happen for a repository that does exist but that has not yet published any images?

[KesleyDavid]

Good catch — you’re right.

A 404 from the Hub API is already mapped to repository or tag not found. Hitting count === 0 / empty results on a 200 is a different case: the repository is there, it just doesn’t have any tags published yet.

I’ve updated the message to no tags found and adjusted the unit tests to match. Thanks for spotting that.

[KesleyDavid]

Thanks for the review, @PyvesB.

Pushed a small fix for the empty-results path: that case now surfaces as no tags found instead of repository not found, since a missing repo/tag already comes through as a 404. Left the dogstatsd example as-is 🐶

[PyvesB]

Thanks for another good contribution!