Update to Airflow 2.0.1

[xylar]

Checklist

• [x] Used a personal fork of the feedstock to propose changes
• [ ] Bumped the build number (if the version is unchanged)
• [x] Reset the build number to 0 (if the version changed)
• [x] Re-rendered with the latest conda-smithy (Use the phrase code>@<space/conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• [x] Ensured the license file is being packaged.

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-linting service.

I wanted to let you know that I linted all conda-recipes in your PR (recipe) and found some lint.

Here's what I've got...

For recipe:

• The outputs section contained an unexpected subsection name. entry_points is not a valid subsection name.

[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]

@halldc and @sodre, this is a pretty massive update. Happy to comment on it or discuss it. Let me know if you want to (and have time to) review. If not, I'll do the best I can.

[xylar]

Many of the airflow-with-* packages have moved to their own packages apache-airflow-providers-* on pypi. I have created the 4 that airflow itself depends on. I will create the others as I'm able once this goes in (see #62). There is a relatively easy series where the dependencies already exist on conda-forge and another where dependencies will have to be added.

[xylar]

I'll try to patch the md5sum issue for OSX.

[xylar]

I'm going to merge this tomorrow unless I hear back.