Automatic merge from submit-queue

Remove federated-image.tag from the .gitignore file.

This generated version metadata file was being written to a source
directory and caused a lot of pain. We are moving to a world where
this file is generated in the build/output artifacts directory and
also possibly looking at ways to entirely remove the federation
specific versions file. This is in-line with that goal of removing
the dependency on federated-image.tag file.

cc @kubernetes/sig-federation-misc