Upstream supports spec.deployments by https://github.com/knative/operator/pull/472 but downstream installs Kourier outside of "official" directory - see SRVKS-721.
So we need to support it by downstream code.

In short, the following configuration adds labels and annotations to 3scale-kourier-control.

apiVersion: operator.knative.dev/v1alpha1
kind: KnativeServing
metadata:
  name: ks
  namespace: knative-serving
spec:
  deployments:
  - name: 3scale-kourier-control
    labels:
      mylabel: foo
    annotations:
      myanno: bar