Add ipython_genutils dependency to 5.5.x branch.

[carlosperate]

#759

This was an implicit dependency via Traitlets, but it was removed in version 5.1 and needs to be explicitly included now.

[blink1073]

Looks like we need to add it to build reqs as well:

ipykernel/pyproject.toml

Line 3 in b773684

"setuptools",

[carlosperate]

I'll try that, but I think I might need to move from ipython_genutils.path import filefind in ipykernel/connect.py (which is imported at the time the wheel is built via __init__.py) as done here: 10044cc

[carlosperate]

Oh wait, I didn't realised that was a pyproject.toml file, you are probably right and that could be enough!

[blink1073]

Thank you!

[carlosperate]

Awesome, thanks @blink1073!