Bump markdown-it-py requirements

[LecrisUT]

Any documented issues for pinning the requirements or markdown-it-py to <3.0.0? Is there a CI for testing the requirement pinnings, especially those in the main dependencies?

[mwouts]

There are no issue that I am aware of. We test the different conversions on a broad collection of notebooks so indeed it would be a great idea to run these tests on the CI with various versions of the dependencies. Would you like to open a PR for that? Thank you

[LecrisUT]

Sure, but I can't do the tests locally (missing git module?) and to do it in CI will need #1041 at the very least

[mwouts]

@LecrisUT , thank you for your help with the github actions! I have prepared a PR at #1087, can you have a look and let me know if that's what you were thinking? Thank you