kubernetes: Fix Federation example in README
Remove `fallthrough` from the federation example in the README.  `fallthrough` isn't needed here and has no effect (federation has an implicit fallthrough for non-federated queries).
It's inclusion is confusing.
@@ -167,10 +167,8 @@ feature enables serving federated domains from the kubernetes clusters.
cluster.local {
federation {
- fallthrough
prod prod.example.org
staging staging.example.org
-
}
kubernetes
}
