Replace setuptools to poetry

[quanpython]

No description provided.

[ReiHashimoto]

In my environment, I get following warning message.
(After updating poetry.lock by poetry lock --no-update, the message disappear in my env.)

Warning: poetry.lock is not consistent with pyproject.toml. You may be getting improper dependencies. Run `poetry lock [--no-update]` to fix it.
Path /private/var/folders/sy/f16zz6x50xz3113nwtb9bvq00000gp/T/abs_6cp367xbh2/croot/python-build_1679596513195/work for build does not exist

And more, there is a following error.

Installing ruamel-yaml (0.18.4): Failed

  RuntimeError

  Unable to find installation candidates for ruamel-yaml (0.18.4)

Do these reproduce in your environment?
If so, I hope them to be fixed.

[quanpython]

@ReiHashimoto
I updated the poetry.lock file and specify version of ruamel.yaml. It seems the error has been resolved.
Please check it again.

[ReiHashimoto]

@quanpython
I made following changes by myself.

• sphinx-pyproject can only parse [project] but [tool.poetry] in pyproject.toml. -> I decided not to use this package.
• sphinx_rtd_theme has problem with version -> update lock file.