Bug: invalid type converter (#1842)

* temporary test case

* remove buggy converter

tests/core/test_db.py

@@ -0,0 +1,12 @@
+from datetime import date
+
+import pytest
+
+from lnbits.db import POSTGRES
+
+
+@pytest.mark.asyncio
+async def test_date_conversion(db):
+    if db.type == POSTGRES:
+        row = await db.fetchone("SELECT now()::date")
+        assert row and type(row[0]) == date