Fix sqlite timezone-naive adapter recipe

Author: NekrodNIK

Doc/library/sqlite3.rst

@@ -2288,7 +2288,7 @@ This section shows recipes for common adapters and converters.
 
    def adapt_datetime_iso(val):
        """Adapt datetime.datetime to timezone-naive ISO 8601 date."""
-       return val.isoformat()
+       return val.replace(tzinfo=None).isoformat()
 
    def adapt_datetime_epoch(val):
        """Adapt datetime.datetime to Unix timestamp."""