Pytorch-ie

:boom: Breaking Changes

* auto-conversion requires a matching entry in `document_converters` (360) ArneBinder
* adjust generic document types (359) ArneBinder

:beetle: Fixes

* Fix `document_type` property of taskmodules (361) ArneBinder

:beetle: Fixes

* save entries of `token_offset_mapping` as lists in document metadata (356) ArneBinder

* add `sum` to default aggregation functions for `LabelCountCollector` (354) ArneBinder
* upgrade `LabeledSpanLengthCollector` to `SpanLengthCollector` (352) ArneBinder
* infer labels in `LabelCountCollector` (351) ArneBinder

:beetle: Fixes

* Fix document types with partitions (349) ArneBinder
* handle `split` parameter for `DatasetDict.load_dataset()` (348) ArneBinder

* (de-)serialize `document_type` when calling `DatasetDict.(to|from)_json()` (346) ArneBinder

* `document_type` for `DocumentMetric`s (343) ArneBinder
* implement `resolve_optional_document_type()` (344) ArneBinder