Test failures with Python 3.12

[mgorny]

When running the test suite with Python 3.12.0, I'm getting two test failures:

======================================================================
FAIL: test_recursion (test.test.TestEncodeDecodeFpExt.test_recursion)
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Traceback (most recent call last):
  File "/tmp/py-ubjson/test/test.py", line 476, in test_recursion
    with self.assert_raises_regex(RuntimeError, 'recursion'):
AssertionError: RuntimeError not raised

======================================================================
FAIL: test_recursion (test.test.TestEncodeDecodePlainExt.test_recursion)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/tmp/py-ubjson/test/test.py", line 476, in test_recursion
    with self.assert_raises_regex(RuntimeError, 'recursion'):
AssertionError: RuntimeError not raised

[vtermanis]

It's probably a change in the default recursion limit with the latest version of Python - I'll have a look later.