NumPy 2.0 support for IOs

[zm711]

We also need to start seeing which IOs are potentially not 2.0 ready. This is just a draft to start assessing this.

This is much better than I was expecting :)

FAILED neo/test/rawiotest/test_blackrockrawio.py::TestBlackrockRawIO::test_compare_blackrockio_with_matlabloader - KeyError: np.int64(-1)
FAILED neo/test/rawiotest/test_blackrockrawio.py::TestBlackrockRawIO::test_compare_blackrockio_with_matlabloader_v21 - OverflowError: Python integer -1 out of bounds for uint16
FAILED neo/test/rawiotest/test_blackrockrawio.py::TestBlackrockRawIO::test_read_all - KeyError: np.int64(-1)
FAILED neo/test/rawiotest/test_plexonrawio.py::TestPlexonRawIO::test_read_all - OverflowError: Python integer 4294967296 out of bounds for uint16