`READONLY` Transactions do not work

I was working on adding read only transactions support to the go client but found it does not work.

Here's my implementation for the go client:

func (h *hranaV2Conn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error) {
    var beginSQL string
    if opts.Isolation != driver.IsolationLevel(sql.LevelDefault) {
        return nil, fmt.Errorf("isolation level %d is not supported", opts.Isolation)
    }
    if opts.ReadOnly {
        beginSQL = "BEGIN TRANSACTION READONLY"
    } else {
        beginSQL = "BEGIN"
    }
    _, err := h.ExecContext(ctx, beginSQL, nil)
    if err != nil {
        return nil, err
    }
    return &hranaV2Tx{h}, nil
}

Here's the test I wrote:

func (t Table) beginReadOnlyTx() Tx {
    txOptions := &sql.TxOptions{ReadOnly: true}
    tx, err := t.db.BeginTx(t.db.ctx, txOptions)
    t.db.t.FatalOnError(err)
    return Tx{tx, t, nil}
}

func TestReadOnlyTransaction(t *testing.T) {
    db := getDb(T{t})
    table := db.createTable()
    tx := table.beginReadOnlyTx()
    tx.assertRowsCount(0)
    tx.insertRows(0, 10)
    db.t.FatalOnError(tx.Commit())
    table.assertRowsCount(0)
}

The results of the test should be 0 rows inserted since it is a read only transaction but 10 rows get inserted.

Start with the Go client's BeginTx implementation shown in the issue and run the TestReadOnlyTransaction test. Check why the read-only transaction still permits inserts; done means the test observes zero inserted rows after commit.