nbconvert version is too strict and other dependencies

[unkcpz]

aiidalab-widgets-base/setup.cfg

Line 33 in 035047f

nbconvert<6

Hi @yakutovicha, do you remember why this has to be pinned with nbconvert<6? I think we can go through the dependencies and polish them.

[yakutovicha]

Honestly, I don't. I agree - we should revise the dependencies. It should probably go along with enabling tests.

[unkcpz]

This is closed by #395