LICENSE of sigs.k8s.io version 1.3.0 cannot be parsed

[thallgren]

The LICENSE file of sigs.k8s.io now contains an extra "Files other than internal/golang/* licensed under:" text at the top, rendering it useless for a regexp starting with \A. An upgrade to version 1.3.0 is currently impossible.

[thallgren]

I created #kubernetes-sigs/json/issues/12 at their side.