Update ipykernel to >= 6.0

[ptheywood]

Is your feature request related to a problem? Please describe.
ipykernel <= 6.0.0a4 does not show stdout or stderr within the notebook display.
This was fixed by ipykernel 6.0.0a5, speciifcally ipython/ipykernel#630

Describe the solution you'd like
ipykernel to be updated to >= 6.0.0

Describe alternatives you've considered
Manually upgrading ipykernel within an active session generally works (after a kernel restart), but is understandably not recommended and will probably cause issues.

Additional context
Python bindings for a CUDA C++ library which uses NVRTC for runtime compilation of CUDA kernels outputs compialtion errors to stdout, which are not visible when using Colab (or other notebooks with ipykernel < 6.0.0a5

[cperry-goog]

This is on our radar, no specific timeline right now. Thanks.

[tburnett]

I found the need to update ipython, the default 5.5.0 failed to render my markdown output with HTML content. Requiring the update triggers the need to restart, an annoyance for me and my users. (I also need an updated scipy, but that updates easily.) This seems to be unrelated to the ipykernel version, but let me + this request to add recent versions of all the modules one expects in the jupyterlab environment--please remove this shadow on such a wonderful contribution to jupyter notebook-based collaboration.

[nika-qubit]

+1 to upgrade ipykernel to v6 as it now supports Jupyter native debugger.

There is some non-backward change from ipython v6 to v7 that display package path is re-arranged. But once ipython is updated, both ipython v7 and v8 work with ipykernel v5+.

TL;DR: coming from apache/beam#23599