Unable to insert data of Map.

```sql
CREATE TABLE IF NOT EXISTS db_ide.test (
    id Int8,
    data Map(String, String)
) ENGINE = MergeTree
ORDER BY (id);
```

```javascript
  await clickhouse.insert(
    `insert into db.test (id, data)`,
    {
      id: 11,
      data: {a : '123'}
    }
  ).toPromise()
```

result:  Failed to insert data. it's empty in database;


ps. this merge resolved #123 