Pin to ipykernel<6 for the docs

[jtpio]

Fixes #3154

[github-actions]

👈 Launch a binder notebook on branch jtpio/ipywidgets/docs-build

[jtpio]

Looking at the RTD logs, it looks like it was pulling ipykernel==6.0.0a0:

https://readthedocs.org/api/v2/build/13206952.txt

[jtpio]

cc @ianhi I think we could keep this pin until ipykernel stabilizes.

[ianhi]

Using ipywidgets fails for me with ipykernel 6a. So maybe this isn't the correct fix?

[ianhi]

See #3157

Should we merge this anyway in order to have the docs work on any new PRs?

[jtpio]

Using ipywidgets fails for me with ipykernel 6a. So maybe this isn't the correct fix?

Isn't it the same issue? Since RTD was pulling ipykernel==6.0.0a0 (probably because of a --pre somewhere)

Should we merge this anyway in order to have the docs work on any new PRs?

It should be ready to go yes, and we can continue tracking this in #3157.

[ianhi]

Isn't it the same issue? Since RTD was pulling ipykernel==6.0.0a0 (probably because of a --pre somewhere)

Yeah the same issue, but my thought was just that this was more so fixing a symptom rather than the root cause.

Should we merge this anyway in order to have the docs work on any new PRs?

It should be ready to go yes, and we can continue tracking this in #3157.

right on. thanks!

[jtpio]

Yeah the same issue, but my thought was just that this was more so fixing a symptom rather than the root cause.

Sure. I think the root cause is being investigated in ipython/ipykernel#602