Fix flaky windows tests

[akhmerov]

There's a warning about IOPub timeout and the failures are nondeterministic.

[choldgraf]

perhaps the hackiest-but-fastest thing to do is to add a couple of catches to re-run this test if it fails with that error automatically. That way the test would only fail if it fails 3 times in a row or something

[akhmerov]

NB This seems to be the same issue: mwouts/jupytext#489

The solution from jupytext side was to skip all tests that execute notebooks on windows...

[chrisjsewell]

theres a pytest plugin for that: https://github.com/pytest-dev/pytest-rerunfailures

[chrisjsewell]

but the more complete fix would be to add an IOPub timeout option to parse to nbclient

[chrisjsewell]

https://github.com/jupyter/nbclient/blob/09dbc75ac83e3df322a2a9fb614d4c82f40b6fe9/nbclient/client.py#L176

[akhmerov]

Didn't seem to help on jupytext side: mwouts/jupytext#489 (reference)

There's a draft PR against nbconvert, that claims to fix this jupyter/nbconvert#1183