Store image digests from a build step #504
Description
Looking at #497 it looks like some progress was made on this but it stalled out. I didn't want to add a bunch of noise to the PR, so I'm opening this issue.
It would be really useful for the image digests to be added to the build metadata in the same way the image tag is currently.
Additionally, it would be great if there was an option for a run command to take any digest values from the build metadata and use them to ensure the run step uses exactly the container image that was built earlier.