Add x86_64-pc-windows-gnu

[AntoinePrv]

Checklist

• Used a personal fork of the feedstock to propose changes
• Bumped the build number (if the version is unchanged)
• Reset the build number to 0 (if the version changed)
• Re-rendered with the latest conda-smithy (Use the phrase @conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• Ensured the license file is being packaged.

Close #261

[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 (recipe/meta.yaml) and found it was in an excellent condition.

I do have some suggestions for making it better though...

For recipe/meta.yaml:

• ℹ️ Use of posix package on windows is deprecated. Use m2-base.
• ℹ️ The recipe is not parsable by parser conda-souschef (grayskull). This parser is not currently used by conda-forge, but may be in the future. We are collecting information to see which recipes are compatible with grayskull.
• ℹ️ The recipe is not parsable by parser conda-recipe-manager. The recipe can only be automatically migrated to the new v1 format if it is parseable by conda-recipe-manager.

_{This message was generated by GitHub Actions workflow run https://github.com/conda-forge/conda-forge-webservices/actions/runs/24504462246. Examine the logs at this URL for more detail.}

[AntoinePrv]

validation results:
  {
    ...
    "noarch/rust-std-x86_64-pc-windows-gnu-1.94.0-unix_0.conda": false,
    ...
  }
  NOTE: Any outputs marked as False are not allowed for this feedstock.
  See https://conda-forge.org/docs/maintainer/infrastructure/#output-validation-and-feedstock-tokens
  for information on how to address this error.

@xhochy @pkgw My understanding is that we need this target for Rust to R packages. What do you think?
If this PR is Ok, I'll move forward with adding an extra recipe output.

[AntoinePrv]

I added a feedstock PR output as well to speed things up if the approach is validated.
conda-forge/admin-requests#2028