OpenAPI Update (#531)

Update OpenAPI for 9ff8230af434f7ea2b30c321a45eb6ebf1d002a9

Co-authored-by: Stripe OpenAPI <105521251+stripe-openapi[bot]@users.noreply.github.com>

embedded/openapi/spec3.beta.sdk.json

@@ -11967,6 +11967,11 @@
             "maxLength": 5000,
             "type": "string"
           },
+          "created": {
+            "description": "Time at which the object was created. Measured in seconds since the Unix epoch.",
+            "format": "unix-time",
+            "type": "integer"
+          },
           "customer": {
             "anyOf": [
               {
@@ -12005,6 +12010,7 @@
         },
         "required": [
           "client_secret",
+          "created",
           "customer",
           "expires_at",
           "livemode",