[Suggestion] Replace `pdm` with `poetry`

[huyfififi]

Is your feature request related to a problem? Please describe.

GitHub Dependabot is not compatible with pdm and cannot check dependencies.

Describe the solution you'd like

https://docs.github.com/en/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file#package-ecosystem

These are the only options that are available for Dependabot. poetry is the most popular one in the industry from my observation.
Without Dependabot, security issues will not be checked.
I think the primarily purpose of this repository is to experience the major procedure of software development, and experience of Dependabot is more rewarding than of pdm. Anyway, poetry is more popular than pdm, so you might find yourself using poetry in other projects.

Describe alternatives you've considered

I haven't checked, but uv of rye is basically the same as pip, so we might be able to configure Dependabot with uv, too.