chore: fix missing namespace in README

[yankay]

After the #86,

#  kubectl get results -o json | jq .
{
  "apiVersion": "v1",
  "items": [],
  "kind": "List",
  "metadata": {
    "resourceVersion": "",
    "selfLink": ""
  }
}

There is no result in the default namespace.
And in the k8sgpt-operator-system namespace, it can work, like:

# kubectl get results -n k8sgpt-operator-system
NAME              KIND      BACKEND   AGE
defaultdao2048    Service   openai    61m
defaultvllmlora   Service   openai    61m

Closes #

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