feat(secret): add support of Docker registry credentials

[bgoareguer]

Description

This blog post shows how to detect Docker registry credentials with Trivy.

I suggest to add the suggested detection rule to the default set of rules in the Trivy code base.

Target

None

Scanner

Secret

[itaysk]

Thanks for reporting. To clarify, this is the suggested rule in the blog: https://gist.github.com/yakirk/f0d5a4cb3893914f956336a9edd32cfe

[knqyf263]

Created #5669