* Vendor changes for go-containerregistry switch.
* Manual changes for go-containerregistry switch.
The biggest change is refactoring the tarball unpacking.
* Pull more of container-diff out.
* More vendor removals.
* More unit tests.
The certs should be added to the whitelisted kaniko directory so that
an image build does not override them and possibly affect the push to
the registry.
Priya Wadhwa
dlorenc
Matt Rickard