[App Store] Search suggestion always returns empty array

Hi, First, thanks for awesome library! I tested search suggestion with your sample code but it always returns an empty array.

```javascript
const itunes = require("aso")("itunes", { country: "us" });
itunes
  .suggest({
    strategy: itunes.SEARCH,
    keywords: ["panda"],
    num: 10
  })
  .then(console.log);
```

