kyverno-disallow-latest-tag.yaml

apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: disallow-latest-tag   
spec:
  validationFailureAction: audit
  background: true
  rules:
  - name: require-image-tag
    match:
      any:
      - resources:
          kinds:
          - Pod
    validate:
      message: "An image tag is required."
      pattern:
        spec:
          containers:
          - image: "*:*"
  - name: validate-image-tag
    match:
      any:
      - resources:
          kinds:
          - Pod
    validate:
      message: "Using a mutable image tag e.g. 'latest' is not allowed."
      pattern:
        spec:
          containers:
          - image: "!*:latest"