Introduce kube-linter into CI workflows to automatically analyze Kubernetes manifests and detect misconfigurations and security issues in the k8s-gitlab-runner repository.

As GitLab runner deployments scale across multiple clusters and instances, we need automated validation of Kubernetes resources to catch operational and security misconfigurations before they reach production.
kube-linter, maintained by StackRox/Red Hat, highlights common risk patterns such as missing resource limits, missing readOnlyRootFilesystem, missing PDBs, unbound services, improper RBAC rules, etc.

Acceptance Criteria

• CI pipeline includes a kube-linter job in the lint stage

• kube-linter processes all manifests rendered via kustomize build

• Job fails on critical rule violations

• Rule exclusions (if any) documented with justification

• Documentation updated with usage instructions

https://docs.kubelinter.io/#/

Just as in https://api.hub.tekton.dev/v1/resource/tekton/task/kube-linter/0.1/raw, you can use docker.io/stackrox/kube-linter