Update to v0.20.0

[xylar]

With this update, we no longer use the cartopy_offlinedata package, we just download the data using cartopy itself.

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.

closes #11

[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.

I do have some suggestions for making it better though...

For recipe:

• License is not an SPDX identifier (or a custom LicenseRef) nor an SPDX license expression.

Documentation on acceptable licenses can be found here.

[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.

[xylar]

@conda-forge-admin, please rerender

[xylar]

@willirath, I've put in a PR that should add the antarctic ice shelves to cartopy downloads: SciTools/cartopy#2097

In the meantime, there's a script here to do that.

I'm downloading the cartopy source code here just so the bot will keep us in sync, though we don't really need to build a new package for every cartopy version.

[xylar]

I'm running some tests with some downstream software (https://github.com/MPAS-Dev/MPAS-Analysis) to make sure there are no surprises.

[willirath]

I'm downloading the cartopy source code here just so the bot will keep us in sync, though we don't really need to build a new package for every cartopy version.

I agree. But closely following cartopy releases also provides immediate warning when cartopy changes anything that breaks our workflow here.

[xylar]

But closely following cartopy releases also provides immediate warning when cartopy changes anything that breaks our workflow here.

Yep, good point. We can always make sure CI passes for each cartopy release even if we just close the PR after that.

[willirath]

Looks good!

[willirath]

All checks passing. @xylar do you want to do more tests, or should we merge?

[xylar]

I got kicked off of the supercomputer where I was doing the testing without explanation! I'll try again elsewhere.

[xylar]

I think my testing job is going to time out before it finishes but it would have shown a bunch of Download warnings if things weren't working.