skaffold dev - some way to force replacement of already tagged/digest images (feature request)

### Expected behavior

`skaffold dev` replaces image tags+digest on any image in the k8s manifests that it builds as part of the pipeline.

### Actual behavior

Images with an existing tag+digest are not touched.

Per #565:

> > Images with fully qualified names (tag or digest) should be left untouched. The user clearly indicated that they want to use a very specific version of the image. That's what need to be fixed

> I don't 100% agree with you here. Perhaps they are just using known-good tags as a starting point, but would like skaffold to replace them when they are iterating on their project.

So it seems like this is intentional. My issue is that I am in the "known-good tags" camp. During development I sometimes want to rebuild and iterate on a shared image as part of a larger Pod, and sometimes want to use the current/default tag+digest for that image. My manifests are generated out-of-band before running `skaffold dev` (the ability to have a custom manifest generator/KRM might help here) so removing the tags is tedious and breaks me out of the dev loop.

What I would like is some way of telling skaffold dev to set all the image tags it has, no matter what existing tags and digests appear in the manifests.