Fix Knative Robots team name
1. Create the appropriate `OWNERS` files (at least one for the root dir).
-1. Make sure that *Serving Robots* is an Admin of the repo.
+1. Make sure that *Knative Robots* is an Admin of the repo.
1. Update the Prow config file (copy and update an existing config for another repo) and run `make update-config`.
