Test failures with pytest 8

[fabaff]

Describe the bug
Multiple tests are failing.

Expected behavior
Tests to pass.

Steps To Reproduce
Run the test suite with pytest 8 and Python 3.11

[...]
ERROR pynetdicom/tests/test_pdu_items.py::TestUserInformation_RoleSelection::test_init - pytest.PytestRemovedIn8Warning: Support for nose tests is deprecated and wi...
ERROR pynetdicom/tests/test_pdu_items.py::TestUserInformation_RoleSelection::test_string_output - pytest.PytestRemovedIn8Warning: Support for nose tests is deprecated and wi...
ERROR pynetdicom/tests/test_pdu_items.py::TestUserInformation_RoleSelection::test_decode - pytest.PytestRemovedIn8Warning: Support for nose tests is deprecated and wi...
ERROR pynetdicom/tests/test_pdu_items.py::TestUserInformation_RoleSelection::test_encode - pytest.PytestRemovedIn8Warning: Support for nose tests is deprecated and wi...
[...]

Using ignore::pytest.PytestRemovedIn8Warning helps for now but is not a permanent solution

Your environment
n/a

[mrbean-bremen]

Duplicate of #840, fixed with #848, needs a new release.