Add escape_json filter

[costimuraru]

Useful when you want to pass a JSON in a terraform file.

resource "kubernetes_secret" "{{repo.name}}-docker-repo-secret" {
  metadata {
    name = "{{repo.name}}-docker-repo-secret"
  }

  data {
    ".dockerconfigjson" = "{{ macros.generate_docker_json_config(repo.repository, repo.credentials) | escape_json }}"
  }

  type = "kubernetes.io/dockerconfigjson"
}