Add upper constraint on ipywidgets

[mattwthompson]

ref nglviewer/nglview#1032

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-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.

[mattwthompson]

@conda-forge-admin, please rerender

[mattwthompson]

The "tests" are failing. I'm going to go out on a limb and say the log is not so useful here:

2022-08-18T21:39:51.1334634Z import: 'nglview'
2022-08-18T21:39:51.7516224Z import: 'nglview'
2022-08-18T21:39:51.8545630Z + jupyter labextension list
2022-08-18T21:39:51.8547708Z + grep -ie 'nglview-js-widgets.*OK'
2022-08-18T21:39:54.2855812Z Tests failed for nglview-3.0.3-pyhd355979_1.tar.bz2 - moving package to /home/conda/feedstock_root/build_artifacts/broken
2022-08-18T21:39:54.2858376Z WARNING:conda_build.build:Tests failed for nglview-3.0.3-pyhd355979_1.tar.bz2 - moving package to /home/conda/feedstock_root/build_artifacts/broken
2022-08-18T21:39:54.3314118Z TESTS FAILED: nglview-3.0.3-pyhd355979_1.tar.bz2
2022-08-18T21:40:01.2802742Z ##[error]Bash exited with code '1'.
2022-08-18T21:40:01.2840502Z ##[section]Finishing: Run docker build

[hainm]

@conda-forge-admin, please rerender

[szcc]

cool. I'll give a try!

[hainm]