Log Message:
py-django-treebeard: updated to 4.3.1

Release 4.3.1:
* Added check to avoid unnecessary database query for ``MP_Node.get_ancestors()``
  if the node is a root node.
* Drop support for Python-3.4.
* Play more nicely with other form classes, that implement ``__init__(self, \ 
*args, **kwargs)``,
  e.g. django-parler's ``TranslatableModelForm``, where `kwargs.get('instance')` \ 
is ``None``
  when called from here.
* Sorting on path on necessary queries, fixes some issues and stabilizes the \ 
whole MP section.
* Add German translation strings.