feat(openapi): add creationTime and modificationTime to policy specs

[schogges]

Motivation

In order to further complete the openAPI specs, we need to add creationTime and modificationTime. These properties are already part of the response payload (see context below). Since the GUI project started to generate the TypeScript types from the specs, there is a high demand in having complete specs to avoid manual backfilling.

Implementation information

Added modificationTime and creationTime to tools/policy-gen/templates/schema.yaml. Afterwards ran make check.

Context

Example Payloads

  {
   "type": "MeshMetric",
   "mesh": "default",
   "name": "otel-metrics.kuma-system",
   "creationTime": "2024-11-05T13:50:03Z",
   "modificationTime": "2024-11-05T13:50:03Z",
   "labels": {
    "k8s.kuma.io/namespace": "kuma-system",
    "kuma.io/display-name": "otel-metrics",
    "kuma.io/mesh": "default",
    "kuma.io/policy-role": "system"
   },
   "spec": {
    "targetRef": {
     "kind": "Mesh"
    },
    "default": {
     "backends": [
      {
       "type": "OpenTelemetry",
       "openTelemetry": {
        "endpoint": "opentelemetry-collector.mesh-observability.svc:4317"
       }
      }
     ]
    }
   }
  }

  {
   "type": "HostnameGenerator",
   "name": "local-mesh-external-service-45zv4bv8cv5v8444.kuma-system",
   "creationTime": "2024-11-05T09:48:59Z",
   "modificationTime": "2024-11-05T09:48:59Z",
   "labels": {
    "k8s.kuma.io/namespace": "kuma-system",
    "kuma.io/display-name": "local-mesh-external-service",
    "kuma.io/env": "kubernetes",
    "kuma.io/mesh": "",
    "kuma.io/origin": "zone",
    "kuma.io/zone": "east"
   },
   "spec": {
    "selector": {
     "meshExternalService": {
      "matchLabels": {
       "kuma.io/origin": "zone"
      }
     }
    },
    "template": "{{ .DisplayName }}.extsvc.mesh.local"
   }
  }

[michaelbeaumont]

Yeah LGTM