Support for poetry 2 lockfile format

[gsemet]

Hello

After switching to poetry 2, it fails with the following exception:

Traceback (most recent call last):
  File "/path/to/the/devenv/.venv/bin/poetry-lock-package", line 8, in <module>
    sys.exit(main())
  File "/path/to/the/devenv/.venv/lib/python3.10/site-packages/poetry_lock_package/app.py", line 188, in main
    run(
  File "/path/to/the/devenv/agpkg/.venv/lib/python3.10/site-packages/poetry_lock_package/app.py", line 222, in run
    dependencies["python"] = parent_project["tool"]["poetry"]["dependencies"]["python"]
KeyError: 'python'