update test to reflect version

Author: masl2

lambdas/letter-updates-transformer/src/mappers/__tests__/letter-mapper.test.ts

@@ -22,7 +22,7 @@ describe("letter-mapper", () => {
     expect(event.dataschema).toBe(
       `https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.PRINTED.${event.dataschemaversion}.schema.json`,
     );
-    expect(event.dataschemaversion).toBe("1.0.5");
+    expect(event.dataschemaversion).toBe("1.0.6");
     expect(event.subject).toBe("letter-origin/supplier-api/letter/id1");
     expect(event.time).toBe("2025-11-24T15:55:18.000Z");
     expect(event.recordedtime).toBe("2025-11-24T15:55:18.000Z");