Add Libsodium

[MementoRC]

Checklist

• [x] Title of this PR is meaningful: e.g. "Adding my_nifty_package", not "updated meta.yaml".
• [x] License file is packaged (see here for an example).
• [x] Source is from official source.
• [x] 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).
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• [x] Build number is 0.
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[conda-forge-webservices[bot]]

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

I was trying to look for recipes to lint for you, but it appears we have a merge conflict. Please try to merge or rebase with the base branch to resolve this conflict.

Please ping the 'conda-forge/core' team (using the @ notation in a comment) if you believe this is a bug.

[conda-forge-webservices[bot]]

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/libsodium) and found some lint.

Here's what I've got...

For recipes/libsodium:

• The license item is expected in the about section.
• Feedstock with the same name exists in conda-forge.

[conda-forge-webservices[bot]]

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/libsodium) and found some lint.

Here's what I've got...

For recipes/libsodium:

• Feedstock with the same name exists in conda-forge.