Code should be compatible with Google Cloud Storage API 2.x

[y26805]

I tried to run the code on Cloud Functions but it didn't work... Upon some investigation I found out that there has been a breaking change in Cloud Storage's API 2.x

Instead of https://github.com/jlaham/audio-2-text/blob/8cd615f436ac7dc3090260a0316df44c7312e852/index.js#L11

it should be

const {Storage} = require('@google-cloud/storage');

(as shown also in the official documentation on npm)