v2.0.2

Small patch with the following bug fixes:

• Added ipywidgets as dependency
• Silenced xgboost warnings
• Handled corner case in bm.metric.auc when scores are all 0
• Fixed error in bm.metric.hmean when metrics were str instead of list
• Fixed error when obs col is list in dc.pp.pseudobulk
• Allowed ordering functions (dc.pp.bin_order, dc.pl.order and dc.pl.order_targets) not to be bound between 0 and 1