Add recipe for pure python package pytorch-pfn-extras

[traversaro]

This is simple pure python package, the recipe was mostly automatically generated from PyPI metadata using rattler-build pypi recipe generation, and modifying it to be compliant with conda-forge guidelines for pure python packages.

PyPI page: https://pypi.org/project/pytorch-pfn-extras
Repo: https://github.com/pfnet/pytorch-pfn-extras

Checklist

• Title of this PR is meaningful: e.g. "Adding my_nifty_package", not "updated meta.yaml".
• License file is packaged (see here for an example).
• Source is from official source.
• Package does not vendor other packages. (If a package uses the source of another package, they should be separate packages or the licenses of all packages need to be packaged).
• If static libraries are linked in, the license of the static library is packaged.
• Package does not ship static libraries. If static libraries are needed, follow CFEP-18.
• Build number is 0.
• A tarball (url) rather than a repo (e.g. git_url) is used in your recipe (see here for more details).
• GitHub users listed in the maintainer section have posted a comment confirming they are willing to be listed there.
• When in trouble, please check our knowledge base documentation before pinging a team.

[github-actions]

Hi! This is the staged-recipes linter and your PR looks excellent! 🚀

[conda-forge-admin]

Hi! This is the friendly automated conda-forge-linting service.

I wanted to let you know that I linted all conda-recipes in your PR (recipes/pytorch-pfn-extras/recipe.yaml) and found some lint.

Here's what I've got...

For recipes/pytorch-pfn-extras/recipe.yaml:

• ❌ The recipe must have a build/number section.

_{This message was generated by GitHub Actions workflow run https://github.com/conda-forge/conda-forge-webservices/actions/runs/14398116754. Examine the logs at this URL for more detail.}

[conda-forge-admin]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipes/pytorch-pfn-extras/recipe.yaml) and found it was in an excellent condition.