Update poetry and doc workflow

[bloebp]

Trying to update poetry and doc workflow.

[bloebp]

@amit-sharma
The build fails due to https://github.com/py-why/dowhy/actions/runs/13867018046/job/38808031740?pr=1302#step:11:660

Any chance we can reduce some dependencies (e.g., is there an alternative way to asses the overlap without using cvxpy)?

[amit-sharma]

the dependency is used for convex optimization, may be difficult to remove.
I checked that ecos package is actually installed. But two versions of cvxpy are installed according to poetry.lock. The problem might be that we are including cvxpy as a conditional install: a different version based on whether python 3.9+ is installed or not.
See pyproject file. Maybe we can try to avoid this conditional import, just like you were able to do with pytorch?