Yaml & Json serialize dates incorrectly

[IvanJosipovic]

Describe the bug
It appears that both Json/Yaml serializers are outputting dates which don't match Kubectl.

For the Test cases below:

Json Output:

{
  "apiVersion": "v1",
  "kind": "Secret",
  "metadata": {
    "creationTimestamp": "2025-09-03T05:15:53.000000\u002B00:00",
    "name": "test-secret"
  },
  "type": "Opaque"
}

Yaml Output:

apiVersion: v1
kind: Secret
metadata:
  creationTimestamp: 2025-09-03T05:15:53.0000000Z
  name: test-secret
type: Opaque

Test cases:

[Fact]
public void ReadWriteDatesJson()
{
    var kManifest = """
    {
        "apiVersion": "v1",
        "kind": "Secret",
        "metadata": {
            "creationTimestamp": "2025-09-03T05:15:53Z",
            "name": "test-secret"
        },
        "type": "Opaque"
    }
    """;

    var objFromJson = KubernetesJson.Deserialize<V1Secret>(kManifest);
    var jsonFromObj = KubernetesJson.Serialize(objFromJson);

    // Format Json
    var jsonFromObj2 = JsonSerializer.Serialize(JsonSerializer.Deserialize<JsonElement>(jsonFromObj), new JsonSerializerOptions() { WriteIndented = true });

    Assert.Equal(kManifest, jsonFromObj2);
}

[Fact]
public void ReadWriteDatesYaml()
{
    var kManifest = """
    apiVersion: v1
    kind: Secret
    metadata:
      creationTimestamp: "2025-09-03T05:15:53Z"
      name: test-secret
    type: Opaque
    """;

    var objFromYaml = KubernetesYaml.Deserialize<V1Secret>(kManifest, true);
    var yamlFromObj = KubernetesYaml.Serialize(objFromYaml);

    Assert.Equal(kManifest, yamlFromObj);
}

Kubernetes C# SDK Client Version
master

Dotnet Runtime Version
net9.0