build: fix poetry

[alandtse]

At least in poetry 2.1.3, it doesn't recognize the prior format as valid.

The Poetry configuration is invalid:
  - Either [project.version] or [tool.poetry.version] is required in package mode.

[mahaloz]

Hmmm is there any other way to allow the dynamic attribute to work for version? I don't like the possiblility of __version__ returning unknown.

I also am not seeing other bigger projects handle this scenario, such as angr:
https://github.com/angr/angr/blob/ff7326dfc1a597f0cc5858ba17d5d4dd930aa482/pyproject.toml#L44