trappy: utils: Fix get_duplicates FutureWarning
Created by: valschneider
We've had this one for a few months now:
trappy/utils.py:78: FutureWarning: 'get_duplicates' is deprecated and will be removed in a future release. You can use idx[idx.duplicated()].unique() instead dups = index.get_duplicates()
Do what the warning says.