No support to specify source with digest

[robinschneider]

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

The tag of the source does not allow using a tag with a digest, e.g. v1.2.3@sha256:26.... There also is no option to set the source image by digest.

Describe the solution you'd like

Add support for tags with digest or at least a separate digest in source.

Describe alternatives you've considered

No response

Additional context

No response