Log Message:
Update django-modelcluster to 6.0

6.0 (14.03.2022)
~~~~~~~~~~~~~~~~
* BREAKING: ClusterForm now builds no child formsets when neither `formsets` nor \ 
`exclude_formsets` is specified in the Meta class, rather than building a \ 
formset for every child relation (Matt Westcott)
* Removed Python 3.5 and 3.6 support
* Removed Django 2.0 and 2.1 support
* Support explicit definitions for nested formsets within ClusterForm, via a \ 
`formsets` option on the outer formset's definition (Matt Westcott)
* Add `inherit_kwargs` attribute to ClusterForm child formsets (Matt Westcott)

5.3 (10.03.2022)
~~~~~~~~~~~~~~~~
* Avoid accessing live queryset on unsaved instances, for preliminary Django 4.1 \ 
compatibility (Matt Westcott)
* Support traversing one-to-one and many-to-one relations in `filter` / \ 
`order_by` lookups (Andy Babic)
* Implement `values()` method on FakeQuerySet (Andy Babic)
* Allow `values()` and `values_list()` to be chained with other queryset \ 
modifiers (Andy Babic)
* Fix: Fix HTML escaping behaviour on `ClusterForm.as_p()` (Matt Westcott)
* Fix: Match standard behaviour queryset of returning foreign keys as IDs in \ 
`values_list` (Andy Babic)

5.2 (13.10.2021)
~~~~~~~~~~~~~~~~
* Implement `copy_cluster` method on ClusterableModel (Karl Hobley)
* Add `formset_name` option on ClusterableModel formsets to allow the formset \ 
name to differ from the relation name (Matt Westcott)
* Fix: Fix tests for Django 3.2 (Alex Tomkins, Matt Westcott, María Fernanda \ 
Magallanes)
* Fix: Ensure ptr_id fields are correctly populated when deserialising models \ 
with multi-level inheritance (Alex Tomkins)