Suggestion: add noarch

[regro-cf-autotick-bot]

I think this feedstock could be built with noarch.
This means that the package only needs to be built once, drastically reducing CI usage.
See here for more information about building noarch packages.
Before merging this PR make sure:

• No compiled extensions
• No post-link or pre-link or pre-unlink scripts
• No OS specific build scripts
• No python version specific requirements
• No skips except for python version. (If the recipe is py3 only, remove skip statement and add version constraint on python)
• 2to3 is not used
• Scripts argument in setup.py is not used
• If entrypoints are in setup.py, they are listed in meta.yaml
• No activate scripts
• Not a dependency of conda
  Notes and instructions for merging this PR:

1. If any items in the above checklist are not satisfied, please close this PR. Do not merge.
2. Please merge the PR only after the tests have passed.
3. Feel free to push to the bot's branch to update this PR if needed.

_{This PR was created by the cf-regro-autotick-bot.
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[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.

[takluyver]

5.6 adds a requirement that's only needed on Python 2 (ipaddress), making the package unsuitable for noarch.