[BUG] CI fails in code_quality isort hook, environment creation, at preparing metadata via pyproject.toml

[fkiraly]

Since a few minutes ago, sktime CI fails at the first step when trying to install the env, with this traceback below.

This seems to be coming from the code_quality job, in there the isort hook when the python environment is being created, probably when trying to parse a pyproject.toml.

As a temporary workaround, isort has been removed here: #4164
but it should be added back.

Below is the traceback:

      Preparing metadata (pyproject.toml): started
      Preparing metadata (pyproject.toml): finished with status 'error'
    
stderr:
      error: subprocess-exited-with-error
      
      × Preparing metadata (pyproject.toml) did not run successfully.
      │ exit code: 1
      ╰─> [14 lines of output]
          Traceback (most recent call last):
            File "/home/runner/.cache/pre-commit/repohskwxkw8/py_env-python3/lib/python3.10/site-packages/pip/_vendor/pep517/in_process/_in_process.py", line 351, in <module>
              main()
            File "/home/runner/.cache/pre-commit/repohskwxkw8/py_env-python3/lib/python3.10/site-packages/pip/_vendor/pep517/in_process/_in_process.py", line 333, in main
              json_out['return_val'] = hook(**hook_input['kwargs'])
            File "/home/runner/.cache/pre-commit/repohskwxkw8/py_env-python3/lib/python3.10/site-packages/pip/_vendor/pep517/in_process/_in_process.py", line 152, in prepare_metadata_for_build_wheel
              return hook(metadata_directory, config_settings)
            File "/tmp/pip-build-env-3kaotqva/overlay/lib/python3.10/site-packages/poetry/core/masonry/api.py", line 40, in prepare_metadata_for_build_wheel
              poetry = Factory().create_poetry(Path(".").resolve(), with_groups=False)
            File "/tmp/pip-build-env-3kaotqva/overlay/lib/python3.10/site-packages/poetry/core/factory.py", line 57, in create_poetry
              raise RuntimeError("The Poetry configuration is invalid:\n" + message)
          RuntimeError: The Poetry configuration is invalid:
            - [extras.pipfile_deprecated_finder.2] 'pip-shims<=0.3.4' does not match '^[a-zA-Z-_.0-9]+$'
          
          [end of output]
      
      note: This error originates from a subprocess, and is likely not a problem with pip.
    error: metadata-generation-failed
    
    × Encountered error while generating package metadata.
    ╰─> See above for output.