fix: doc build without python cache

[SMoraisAnsys]

Following a discussion with @RobPasMue, the implementation of the doc-build action did not correctly take into account the fact of not using caching when installing Python packages.

Note: this is particularly annoying when one works with self-hosted runners where you can easily think that you are using the latest version of a package and it's not the case.

This PR does:

• add --no-cache-dir flag for pip build backend or --no-cache flag for poetry backend if the input asks for no python cache;
• refactoring related to determining whether the backend is poetry or pip.

Extra: to handle poetry and virtual environment, I use poetry config virtualenvs.create false. This configures poetry to not create a new virtual environment and ensure it uses the activated virtual environment. Another approach would have been to use poetry's capability to create a virtual environment in-project. However, this wouldn't work well in the case of our VM with self hosted runners. Indeed, if a virtual environment has already been created for the project under {cache-dir}/virtualenvs, using poetry config virtualenvs.in-project true will not cause poetry to create or use a local virtual environment.
To fix that, a manual deletion of the virtual environment is required but it would troublesome in the long run... Thus, this option is not leveraged.

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[RobPasMue]

Some comments :) otherwise LGTM

[RobPasMue]

venvs and poetry don't get along well AFAIK... Have you tried this with a poetry based project? Also... where is the venv created? I can't see it in this file...

[SMoraisAnsys]

I'll need to check on such repo yeah, I didn't tried yet :)

[RobPasMue]

Please remember to change this

[RobPasMue]

Same here

[SMoraisAnsys]

FYI, I tested this on a fork of pyconceptev as I think poetry handling might have been difficult.

The PR : SMoraisAnsys/pyconceptev#1

The CI associated consists in running multiple workflows where I build the documentation twice:

• Windows/Linux : build documentation with use-python-cache = True, remove virtual environment and build documentation with use-python-cache = True. The packages are downloaded for the first documentation build and not downloaded for the second documentation build.
• Windows/Linux : build documentation with use-python-cache = True, remove virtual environment and build documentation with use-python-cache = False. The packages are downloaded every time to build the documentation!

The idea of those workflow is to mock how a VM would behave when it had been already used with caching.

The logs are here, know that I manually checked and it was consistent.

[SMoraisAnsys]

Tested on pyansys-sound and it worked, see ansys/pyansys-sound#111

[SMoraisAnsys]

Tested in pyansys-geometry and working as expected, see ansys/pyansys-geometry#1404

[SMoraisAnsys]

Closing following #621