Add support for aarch64 python 3.9

[mathbunnyru]

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, please rerender

Fix: #35

[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.

[mathbunnyru]

I copy-pasted aarch64 file for python3.8 and changed the version - is there anything else I should do?

[github-actions]

Hi! This is the friendly automated conda-forge-webservice.
I tried to rerender for you but ran into some issues, please ping conda-forge/core
for further assistance. You can also try re-rendering locally.

[mathbunnyru]

I bumped numpy to 1.19 for this python version - is it ok? I've seen it used in other places as well.

[mathbunnyru]

Seems to work!

[mathbunnyru]

Travis Ci is misbehaving

[github-actions]

Hi! This is the friendly automated conda-forge-webservice.
I tried to rerender for you but ran into some issues, please ping conda-forge/core
for further assistance. You can also try re-rendering locally.

[mathbunnyru]

@jakirkham @msarahan @ocefpaf @qwhelan @wesm may I ask you to take a look please?

[jakirkham]

Why is this being added manually? Did you try re-rendering?

[mathbunnyru]

Thanks, I will take a look at what that means and try to re-render.
Sorry, I'm a beginner in conda-forge maintenance.

[jakirkham]

xref: #37

[jakirkham]

PR ( #38 ) should handle this, but there is a lingering question for one of the maintainers

[mathbunnyru]

Thank you! Hope this will be merged soon :)