newest-build constraint

[dudo]

I'd love to see similar functionality to digest when using newest-build. Specifically, I'd like to lean on the latest tag, but reference a corresponding tag that's paired with it (the 40 character git sha, for instance).

Something like this:

argocd-image-updater.argoproj.io/image-list: 'app=ghcr.io/{{ .organization }}/{{ regexReplaceAll "-deployment$" .repository "" }}:latest'
argocd-image-updater.argoproj.io/app.update-strategy: newest-build
argocd-image-updater.argoproj.io/app.allow-tags: regexp:^[0-9a-f]{40}$

Then when comparing diffs, the date could be used instead of the digest.

This pic shows my use case. The newest image will often not be the image I want deployed to production.

[dudo]

This comment seems relevant

argocd-image-updater/registry-scanner/pkg/image/version.go

Lines 109 to 110 in 10a01f3

	// TODO: Shall we really ensure a valid semver on the current tag?
	// This prevents updating from a non-semver tag currently.