Add new properties to ChatCompletionResponse model

Two new properties, 'Created' and 'SystemFingerprint' have been added to the ChatCompletionResponse model in OpenAI.ChatGpt. 'Created' is a Unix timestamp of when the chat completion was created and 'SystemFingerprint' is a string used to understand if backend configuration changes may affect determinism with respect to the model's usage.

src/OpenAI.ChatGpt/Models/ChatCompletion/ChatCompletionResponse.cs

@@ -14,12 +14,22 @@ public class ChatCompletionResponse
     [JsonPropertyName("object")]
     public string Object { get; set; }
 
+    /// <summary>
+    /// The Unix timestamp (in seconds) of when the chat completion was created.
+    /// </summary>
     [JsonPropertyName("created")]
     public long Created { get; set; }
 
     [JsonPropertyName("model")]
     public string Model { get; set; }
 
+    /// <summary>
+    /// This fingerprint represents the backend configuration that the model runs with.
+    /// Can be used in conjunction with the <see cref="ChatCompletionRequest.Seed"/> request parameter to understand when backend changes have been made that might impact determinism.
+    /// </summary>
+    [JsonPropertyName("system_fingerprint")]
+    public string SystemFingerprint { get; set; }
+
     [JsonPropertyName("choices")]
     public Choice[] Choices { get; set; }