chore: fix issue caused by ownerIsBuiltIn being true by default

[thapabishwa]

Description

Pods without owners are ignored because ownerIsBuiltIn is true by default. As a result the condition in if statement evaluates to true and the Pods without owners are ignored.

trivy-kubernetes/pkg/trivyk8s/trivyk8s.go

Line 156 in 95e88d5

if c.excludeOwned && ownerIsBuiltIn {

This PR adds ownerExists boolean variable to fix this issue.

Before

go run examples/trivy.go
Current namespace: default
Scanning kind 'pods' with exclude-owned=true
Name: pod-with-crd-owner, Kind: Pod, Namespace: kube-system, Images: [nginx:latest]

After

go run examples/trivy.go
Current namespace: default
Scanning kind 'pods' with exclude-owned=true
Name: my-pod, Kind: Pod, Namespace: default, Images: [nginx:latest]
Name: pod-with-crd-owner, Kind: Pod, Namespace: kube-system, Images: [nginx:latest]

[chen-keinan]

lgtm 🚀