Add missing "defaults" field to IndexState (#1054)

Author: swallez

output/schema/schema.json

@@ -27,5 +27,7 @@ export class IndexState {
   aliases?: Dictionary<IndexName, Alias>
   mappings?: TypeMapping
   settings?: IndexSettings
+  /** Default settings, included when the request's `include_default` is `true`. */
+  defaults?: IndexSettings
   data_stream?: DataStreamName
 }