Re-configure registry auth when an extension changes a base or target image reference

[chanseokoh]

(from Gitter)

@alvarosanchez had auth failure for a base image after an extension changed the base image ref to openjdk (i.e., on Docker Hub) from the default gcr.io/distroless/java:8. The root cause is that the credential retrievers set up for the original registry (gcr.io) were being used. We need to re-configure credentials retrievers when the base or target image ref is changed by an extension. Not sure how easy it will be to do so.

[alicejli]

This is still an issue AFAIK, but there is a workaround micronaut-projects/micronaut-maven-plugin#74. Going to keep this open, but there are no current plants to implement this.