Always use \n as new line when generating files with CMake

[traversaro]

As reported in https://github.com/conda-forge/opencv-feedstock/issues/302, \n\r do not represent a single newline in Windows (even as in that case it would be \r\n). Anyhow, \n seems to be working fine, so let's just use that one.

Upstream PR: https://github.com/casadi/casadi/pull/2906 .

Similar PRs:

• https://github.com/robotology/idyntree/pull/981
• https://github.com/artivis/manif/pull/244

Checklist

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

[conda-forge-linter]

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) and found it was in an excellent condition.

[traversaro]

@conda-forge-admin, please rerender