Add Default securityContext

apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: add-default-securitycontext
  annotations:
    policies.kyverno.io/title: Add Default securityContext
    policies.kyverno.io/category: Sample
    policies.kyverno.io/subject: Pod
    policies.kyverno.io/minversion: 1.6.0
    policies.kyverno.io/description: A Pod securityContext entry defines fields such as the user and group which should be used to run the Pod. Sometimes choosing default values for users rather than blocking is a better alternative to not impede such Pod definitions. This policy will mutate a Pod to set `runAsNonRoot`, `runAsUser`, `runAsGroup`, and  `fsGroup` fields within the Pod securityContext if they are not already set.
spec:
  rules:
    - name: add-default-securitycontext
      match:
        any:
          - resources:
              kinds:
                - Pod
      mutate:
        patchStrategicMerge:
          spec:
            securityContext:
              +(runAsNonRoot): true
              +(runAsUser): 1000
              +(runAsGroup): 3000
              +(fsGroup): 2000