Description of problem:

Couple of tests started to fail after 'jwk' field was removed from a container repo, but the field seems to be only optional.

How reproducible:

always

Is this issue a regression from an earlier version:

no, the requirement is there since begining (~3 years)

Steps to Reproduce:

1. try to sync library/busybox from gcr.io

Actual behavior:
Sync fails with
signatures.0.header: 'jwk' is a required property
 

Expected behavior:
Successful sync

Business Impact / Additional info: