v2.2.3 breaks S3Adapter

[blacha]

On upgrading from v2.2.2 to v2.2.3 we are now getting a error with the S3Adapter

Simple case to reproduce:

var ParseServer = require('parse-server').ParseServer;
var S3Adapter = require('parse-server').S3Adapter;
var api = new ParseServer({
    filesAdapter: new S3Adapter()
});

output:

    filesAdapter: new S3Adapter(
                  ^

TypeError: S3Adapter is not a function
    at Object.<anonymous> (/var/app/current/index.js:35:19)
    at Module._compile (module.js:410:26)
    at Object.Module._extensions..js (module.js:417:10)
    at Module.load (module.js:344:32)
    at Function.Module._load (module.js:301:12)
    at Function.Module.runMain (module.js:442:10)
    at startup (node.js:136:18)
    at node.js:966:3