postgres timestamp decoding loses the associated time zone

Postgres timestamp decoding loses the associated time zone and returns a string that represents a different time.

```sql
set x = '2021-01-01T02:00+02:00'::timestamptz;
select 'debug' as component, $x as x;
```

### Actual behavior

```json
{"component":"debug","x":"2021-01-01T01:00:00+00:00"}
```

### Expected behavior

```json
{"component":"debug","x":"2021-01-01T02:00:00+02:00"}
```
