fix: missing generateUnionEnums in .d.ts (#193)

Author: artsaban

index.d.ts

@@ -29,6 +29,11 @@ interface GenerateApiParams {
    */
   templates?: string;
 
+  /**
+   * generate all "enum" types as union types (T1 | T2 | TN) (default: false)
+   */
+  generateUnionEnums?: boolean;
+
   /**
    * generate type definitions for API routes (default: false)
    */