Sample Fix

[AlmogCohen]

Following the issue fix here: https://github.com/googleapis/google-api-nodejs-client/issues/1523, I've realized that one of the NodeJS example has an issue in it. This line has an incorrect auth definition without the auth: option. When using more than one classroom instance it causes login errors. The issue with the docs is here: https://github.com/gsuitedevs/node-samples/blob/master/classroom/quickstart/index.js#L92

[elyobo]

@AlmogCohen the line is correct, check out object shorthand notation.