Fix failing tests and reactivate.

[uermel]

Currently, there are 5 failing tests:

• tests/test_augmentations.py::test_mixup_transform - assert False
• tests/test_dataset_examples.py::TestDatasetExamples::test_class_name_to_filename_consistency - TypeError: setup_logging() got an unexpected keyword argument 'level'
• tests/test_minimal_dataset.py::TestMinimalCopickDataset::test_class_to_label_consistency - TypeError: '<=' not supported between instances of 'int' and 'MagicMock'
• tests/test_minimal_dataset.py::TestMinimalCopickDataset::test_dataset_initialization - AssertionError: Items in the first set but not the second:
• tests/test_simple_dataset_docs.py::TestSimpleDatasetDocs::test_class_name_to_filename_consistency - TypeError: setup_logging() got an unexpected keyword argument 'level'

to unblock release I'm deactivating. lmk if these are essential @kephale.