Support python 3.12+

[guiguem]

It seems that some modules like ConfigParser have changed with python3.12; when running t2kdm-config installed with python 3.12 I get:

❯ t2kdm-config
Traceback (most recent call last):
  File "/opt/homebrew/anaconda3/envs/my-dirac-env/bin/t2kdm-config", line 8, in <module>
    sys.exit(run_configuration_wizard())
             ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/anaconda3/envs/my-dirac-env/lib/python3.12/site-packages/t2kdm/configuration.py", line 138, in run_configuration_wizard
    conf = load_config()
           ^^^^^^^^^^^^^
  File "/opt/homebrew/anaconda3/envs/my-dirac-env/lib/python3.12/site-packages/t2kdm/configuration.py", line 115, in load_config
    return Configuration(testpath, defaults=default_values)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/anaconda3/envs/my-dirac-env/lib/python3.12/site-packages/t2kdm/configuration.py", line 64, in __init__
    self.load_config(filename)
  File "/opt/homebrew/anaconda3/envs/my-dirac-env/lib/python3.12/site-packages/t2kdm/configuration.py", line 70, in load_config
    parser = configparser.SafeConfigParser(self.defaults)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: module 'configparser' has no attribute 'SafeConfigParser'. Did you mean: 'RawConfigParser'?