Add libcap to global pinnings

[hmaarrfk]

xref: conda-forge/libcap-feedstock#48 Thank you @ehfd This is the kind of PR you can do to start the migrations ^_^

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.

[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.

[ehfd]

OK, I will reference this format in the future.

[hmaarrfk]

there is an example file in the same directory that i copy over all the time.