Cannot fork the postman collection for Anomaly Detection

> Please provide us with the following information:
> ---------------------------------------------------------------

### This issue is for a: (mark with an `x`)
```
- [ ] bug report -> please search issues before submitting
- [ ] feature request
- [X] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)
```

### Minimal steps to reproduce
> Go to "https://github.com/Azure-Samples/AnomalyDetector/tree/master/postman-demo" and try to download the Postman collection

### Any log messages given by the failure
> No permission

### Expected/desired behavior
> I would like to download the collection without any permission issues. Is the collection publicly available?

### OS and Version?
> Windows 7, 8 or 10. Linux (which distribution). macOS (Yosemite? El Capitan? Sierra?)

### Versions
>

### Mention any other details that might be useful

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