Fix python 3.6 and windows builds.

[jasongrout]

From @isuruf on the conda-forge gitter channel: https://gitter.im/conda-forge/conda-forge.github.io?at=5bbb8adb271506518dd861b7

python matrix builds are used if you have just - python as a requirement.
- python >= 3.5 means conda-build can use any python version >= 3.5 as a run requirement, but what we actually want is the python version that it built against as the run requirement”

Checklist

• Used a 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-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.

[jasongrout]

@conda-forge-admin, please rerender

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-webservice.

I tried to re-render for you, but it looks like there was nothing to do.

[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.

[jasongrout]

Fixes our changes at #144

[jasongrout]

Checked the circleci py36 log, and indeed the python 3.6 package is getting built, not the python 3.7 package like before.

[blink1073]

afk, but I think this same issue might be occuring with the latest ipython and jupyter_console feedstock releases.

[blink1073]

LGTM, thanks!

[jasongrout]

Thanks! Everything is passing now, so merging.

[jasongrout]

afk, but I think this same issue might be occuring with the latest ipython and jupyter_console feedstock releases.

ipython looks fine, and it turns out that in noarch packages (like jupyter_console), constraining the python version is the right way to do it (and in fact, skip lines in noarch packages fail in the linter).

[blink1073]

Great, thanks for checking!