get_offset_position deprecated (used in exporter.py)

[hyanwong]

With newer matlibplot versions, I get

mpld3/mplexporter/exporter.py:267: MatplotlibDeprecationWarning: 
The get_offset_position function was deprecated in Matplotlib 3.3 and will be removed two minor releases later.
  offset_order = offset_dict[collection.get_offset_position()]

[jasjisdo]

Collection's offset_position has been removed

[felipems11]

Try replacing this line by: offset_order = dict()
This worked for me, but I understand this is an awful solution.

#offset_order = offset_dict[collection.get_offset_position()]
offset_order = dict()