Bad progress bar rendering

Got has spontaneously developed a problem printing progress bars:

```
$ got project/repo
project/repo: no local clone on record
Cloning ssh://... to C:\repos\project\repo
(0 of <class 'progressbar.base.UnknownLength'>) |#    
```

I assume [progressbar2](https://pypi.org/project/progressbar2/3.37.0/) has changed something in a recent update