Add butane

[freundTech]

Checklist

• Title of this PR is meaningful: e.g. "Adding my_nifty_package", not "updated meta.yaml".
• License file is packaged (see here for an example).
• Source is from official source.
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• Build number is 0.
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[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 (recipes/butane/meta.yaml) and found it was in an excellent condition.
I do have some suggestions for making it better though...

For recipes/butane/meta.yaml:

• Jinja2 variable references are suggested to take a {{<one space><variable name><one space>}} form. See lines [14].

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

[freundTech]

@conda-forge/help-go, ready for review!