Epoch iterator for run_pl_ner.py
Dear all,

While training the run_pl_ner.py code, with increasing documents added the epoch iterator increases. But with this increase, it also prints a new line making the progress bar for the epoch span on multiple lines as shown below. I was wondering if there is a way to restrict this multi-line progress bar to one line?

Thank You. 

![image](https://user-images.githubusercontent.com/45199062/90014027-a6d6d380-dca6-11ea-86d0-1ccc5f820d18.png)

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.
