v2.0 added a security check that prevents kustomizations from reading files outside their own directory root.
This was meant to help protect the person inclined to download kustomization directories from the web and use them without inspection to control their production cluster (see #693, #700, #995 and #998)
Resources (including configmap and secret generators)
can still be shared via the recommended best practice
of placing them in a directory with their own
kustomization file, and refering to this directory as a
base from any kustomization that
wants to use it. This encourages modularity and
relocatability.
To disable this, use v3, and the load_restrictor flag:
kustomize build --load_restrictor none $target