Add ProgressBar for `to_parquet`
Thanks for your proposal, @zanussbaum. Yes, I agree that would definitely be a nice feature to have! @albertvillanova I’m happy to make a quick PR for the feature! let me know  That would be awesome ! You can comment `#self-assign` to assign you to this issue and open a PR :) Will be happy to review Closing as this has been merged @lhoestq 
### Feature request

Add a progress bar for `Dataset.to_parquet`, similar to how `to_json` works.

### Motivation

It's a bit frustrating to not know how long a dataset will take to write to file and if it's stuck or not without a progress bar

### Your contribution

Sure I can help if needed