Promisify

BREAKING CHANGES:

1. Node v10+ supported only. Support for versions bellow was dropped.
2. All existing consumer will have to change the way library is used.

From:

maxmind.open('db.mmdb', options, (err, lookup) => { ... })
// or
const lookup = maxmind.openSync('db.mmdb', options);
lookup.get('1.2.3.4');

To:

const lookup = await maxmind.open('db.mmdb', options);
lookup.get('1.2.3.4');