Kaniko multistage builds that have images built on previously built images fail with manifest_unknown

[giesberge]

Actual behavior
When I do something like

FROM busybox as base
RUN echo 'Doing something here'

FROM base as nextstep
RUN echo 'Doing something else here'

I will get an error like the following
Retrieving image base from dockerhbu error building image: unable to complete operation after 0 attempts, last error: GET base/manifests/latest: MANIFEST_UNKNOWN: The named manifest is not known to the registry.; map[manifest:library/base]

Expected behavior
I expect to be able to successfully build an image

To Reproduce
Steps to reproduce the behavior:

1. Generate dockerfile like above
2. Kaniko build with --target nextstep

Additional Information

• All should be above.

Triage Notes for the Maintainers

Description	Yes/No
Please check if this a new feature you are proposing	- No
Please check if the build works in docker but not in kaniko	- Yes
Please check if this error is seen when you use --cache flag	- No
Please check if your dockerfile is a multistage dockerfile	- Yes