Add cuda-nvtx constraints.

[bdice]

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.

We are adding cuda-nvtx which will supersede this package. We'll soon update the nvtx Python package to use that instead of nvtx-c. conda-forge/staged-recipes#22052

[conda-forge-webservices]

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.

[bdice]

@conda-forge-admin, please rerender

[bdice]

Pausing this for the moment while we figure out some upstream questions about cuda-nvcc. I’ll close for now and reopen if/when relevant.