feat: Add previous_attempt_url

- Add missing `previous_attempt_url` property.
- Sort properties according to the schema.

src/Octokit.Webhooks/Models/WorkflowRun.cs

@@ -92,16 +92,19 @@ public sealed record WorkflowRun
         [JsonPropertyName("workflow_url")]
         public string WorkflowUrl { get; init; } = null!;
 
-        [JsonPropertyName("actor")]
-        public User Actor { get; init; } = null!;
-
         [JsonPropertyName("run_attempt")]
         public long RunAttempt { get; init; }
 
         [JsonPropertyName("run_started_at")]
         [JsonConverter(typeof(DateTimeOffsetConverter))]
         public DateTimeOffset RunStartedAt { get; init; }
 
+        [JsonPropertyName("previous_attempt_url")]
+        public string? PreviousAttemptUrl { get; init; }
+
+        [JsonPropertyName("actor")]
+        public User Actor { get; init; } = null!;
+
         [JsonPropertyName("triggering_actor")]
         public User TriggeringActor { get; init; } = null!;
     }