Revert to own generated type (#46)

* Revert to own generated type

* Add changeset

Author: valtyr

.changeset/proud-moons-listen.md

@@ -0,0 +1,5 @@
+---
+"prisma-kysely": patch
+---
+
+Bugfix: revert to own generated type, that supports ColumnType

src/helpers/generateFile.ts

@@ -19,7 +19,10 @@ export const generateFile = (
 
   const result = printer.printFile(file);
 
-  const leader = `import type { ColumnType, Generated, GeneratedAlways } from "kysely";
+  const leader = `import type { ColumnType, GeneratedAlways } from "kysely";
+export type Generated<T> = T extends ColumnType<infer S, infer I, infer U>
+  ? ColumnType<S, I | undefined, U>
+  : ColumnType<T, T | undefined, T>;
 export type Timestamp = ColumnType<Date, Date | string, Date | string>;`;
 
   if (withEnumImport) {