Improve debug info

[marxsk]

(node:19748) UnhandledPromiseRejectionWarning: Error: App not found (404)
at /home/vps/appscraper/node_modules/google-play-scraper/lib/utils/request.js:41:19
at runMicrotasks (<anonymous>)
at processTicksAndRejections (internal/process/task_queues.js:97:5) 

It would be nicer to have more information there as many of us works with multiple applications. I suggest to add there whole opts. But I'm open about what should be displayed

app-store-scraper/lib/app.js: line 17 throw Error(App not found (404): ${JSON.stringify(opts)});