adjust leveldb version

[ValentynKH]

Had issue running application on node v18.16.0

'Database backend leveldown not found'

/**

• backends.js - database backends for bcoin
• Copyright (c) 2014-2017, Christopher Jeffrey (MIT License).
• https://github.com/bcoin-org/bcoin
  */

'use strict';

exports.get = function get(name) {
if (name === 'memory')
return require('./memdb');

try {
return require(name);
} catch (e) {
if (e.code === 'MODULE_NOT_FOUND')
throw new Error('Database backend "' + name + '" not found.');
throw e;
}
};