Update generated code for v1574

Author: stripe-openapi[bot]

OPENAPI_VERSION

@@ -1 +1 @@
-v1573
+v1574

src/Stripe.net/Services/Invoices/InvoiceSubscriptionDetailsCancelAt.cs

@@ -0,0 +1,13 @@
+// File generated from our OpenAPI spec
+namespace Stripe
+{
+    public class InvoiceSubscriptionDetailsCancelAt : StringEnum
+    {
+        public static readonly InvoiceSubscriptionDetailsCancelAt MinPeriodEnd = new InvoiceSubscriptionDetailsCancelAt("min_period_end");
+
+        private InvoiceSubscriptionDetailsCancelAt(string value)
+            : base(value)
+        {
+        }
+    }
+}

src/Stripe.net/Services/Invoices/InvoiceSubscriptionDetailsOptions.cs

@@ -33,12 +33,12 @@ public class InvoiceSubscriptionDetailsOptions : INestedOptions
         /// proration for that period.
         /// </summary>
         [JsonProperty("cancel_at")]
-        [JsonConverter(typeof(UnixDateTimeConverter))]
+        [JsonConverter(typeof(AnyOfConverter))]
 #if NET6_0_OR_GREATER
         [STJS.JsonPropertyName("cancel_at")]
-        [STJS.JsonConverter(typeof(STJUnixDateTimeConverter))]
+        [STJS.JsonConverter(typeof(STJAnyOfConverter))]
 #endif
-        public DateTime? CancelAt { get; set; }
+        public AnyOf<DateTime?, InvoiceSubscriptionDetailsCancelAt> CancelAt { get; set; }
 
         /// <summary>
         /// This simulates the subscription being canceled or expired immediately.