The serving-operator should export prometheus metrics #5

apiVersion: v1
kind: Service
metadata:
  labels:
    app: serving-operator
    serving.knative.dev/release: devel
  name: serving-operator
  namespace: default
spec:
  ports:
  - name: metrics
    port: 9090
    protocol: TCP
    targetPort: 9090
  selector:
    app: serving-operator