fix: switch to kernel_manager_class

[flying-sheep]

Sorry for that. Trying to use the new feature, I realized that jupyter_cache doesn’t have a way to close the kernel client and neither does nbclient’s execute, seems like they don’t really test that API.

This variant works, since it goes down the owns_kc path and therefore shuts down everything nicely.

This time I actually checked if it works as expected: flying-sheep/sphinx-exec-jupyter#33

[bsipocz]

Thanks @flying-sheep for the follow-up. I'm pretty sure the rtd failure is unrelated but I'll have to have a closer code when I'm back at the keyboard before merging this.

[flying-sheep]

Thank you! Again, very sorry, I didn’t consider this.

[bsipocz]

RTD failure is unrelated, so let's have this in. Thanks @flying-sheep!