Unable to save additional metrics due to encoding issues #368
Description
When the encoding of data (such as feature names) does not match the one of the system (for example, when data is encoded with utf-8 under many Windows systems), additional metrics cannot be saved, raising issues such as:
2021-04-04 15:52:32,312 supervised.utils.additional_metrics ERROR Exception while saving additional metrics. 'charmap' codec can't encode character '\u025b' in position 78: character maps to <undefined>
mljar is smart enough to just skip over the exception, so it is not such a big problem, but it limits usefulness particularly for data exploration.
A fix could be to have the .save_* methods of AdditionalMetrics (supervised/utils/additional_metrics.py) accept an encoding. A "good enough" alternative might be to explicitly add an encoding="utf-8" to all such methods, noting it in the documentation as the default encoding.