Python runtime tests fail for new Python 3.12.3

[mikir]

Zserio version and language Zserio: 2.13 Language: Python 3.12.3

Describe the bug If new Python version 3.12.3 is used, the Python runtime tests fail with the following error:

ERROR: test_enum_array (test_array.ArrayTest.test_enum_array)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/runner/work/zserio/zserio/compiler/extensions/python/runtime/tests/test_array.py", line 186, in test_enum_array
    self._test_array(array_traits, array1_values, array1_bitsizeof, array1_aligned_bitsizeof, array2_values)
  File "/home/runner/work/zserio/zserio/compiler/extensions/python/runtime/tests/test_array.py", line 352, in _test_array
    self._test_array_normal(array_traits, array1_values, array1_bitsizeof)
  File "/home/runner/work/zserio/zserio/compiler/extensions/python/runtime/tests/test_array.py", line 435, in _test_array_normal
    read_array_from_reader = Array.from_reader(array_traits, from_reader, len(array_values))
                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/runner/work/zserio/zserio/compiler/extensions/python/runtime/src/zserio/array.py", line 77, in from_reader
    instance.read(reader, size)
  File "/home/runner/work/zserio/zserio/compiler/extensions/python/runtime/src/zserio/array.py", line 320, in read
    append(array_traits_read(reader, index))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/runner/work/zserio/zserio/compiler/extensions/python/runtime/src/zserio/array.py", line 1994, in read
    return self._element_factory.create(reader, index)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/runner/work/zserio/zserio/compiler/extensions/python/runtime/tests/test_array.py", line 170, in create
    return ArrayEnum.from_reader(reader)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/runner/work/zserio/zserio/compiler/extensions/python/runtime/tests/test_object/array_enum.py", line 29, in from_reader
    return cls(reader.read_signed_bits(8))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/runner/work/zserio/zserio/compiler/extensions/python/runtime/src/zserio/enum.py", line 27, in __call__
    obj = super().__call__(value, names, module=module, qualname=qualname, type=type_, start=start)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.3/x64/lib/python3.12/enum.py", line 757, in __call__
    return cls.__new__(cls, value)
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.3/x64/lib/python3.12/enum.py", line 1171, in __new__
    raise ve_exc
ValueError: (0, None) is not a valid ArrayEnum

How to reproduce Steps to reproduce the behavior:

• Install Python 3.12.3.
• If necessary, set envinroment variable PYTHON to python3.12
• Run scripts/build.sh python_rt

Expected behavior No failure, everything should work as usually.

Additional context Python version 3.12.2 works smoothly and without any problem. Please, don't forget to update GitHub actions as well, currently we use fixed Python version 3.12.2.