Loosen `google-cloud-storage` version support and allow greater than 2.0

The library dependency on `google-cloud-storage` looks like this:

```python
"google-cloud-storage >= 1.32.0, < 2.0.0dev",
```

After reading through the changelog for versions 2.0.0 and above, I did not notice any breaking changes. The use of version 2.0.0 and above should be loosened. Thanks!