Set readTimeout to a value greater than switchOverTimeoutSeconds.

[shunki-fujita]

Describe the bug
Since readTimeout is short, it times out earlier than the switchOverTimeoutSeconds given to GetContext.

moco/pkg/dbop/replication.go

Lines 64 to 70 in ffb5b0a

	err = o.db.GetContext(ctx, &timeout, `SELECT WAIT_FOR_EXECUTED_GTID_SET(?, ?)`, gtid, timeoutSeconds)
	if err != nil {
	return fmt.Errorf("failed to wait GTID subset %s: %w", gtid, err)
	}
	if timeout {
	return ErrTimeout
	}

In this case, the error message is as follows, and it is hard to understand that it is a timeout:

  "error": "failed to failover: failed to wait GTID subset aaaa-bbbb-cccc-dddd-efgh:1-10: invalid connection",

The readTimeout setting is as follows:

moco/pkg/dbop/operator.go

Line 20 in ffb5b0a

readTimeout = 1 * time.Minute

For the same reason, failOverTimeoutSeconds is a meaningless value.

Expected behavior
Return ErrTimeout in case of timeout.
switchOverTimeoutSeconds should be shorter than readTimeout.