updating nbconvert

Hi,

I am hoping to update nbconvert to ver 6.0.7 on rawhide. This version introduces several dependencies. Most of the dependencies that I was able to track down have now been packaged and reside in rawhide (except pyppeteer I think).

I would like some help in solving some test failures - see build 1795156 on my COPR [0]. I see OSError related to xelatex but unsure how to proceed.

Any help will be appreciated. Once this is done, I plan to update spyder to 4.2.x.

Thanks, Mukundan.

[0] https://copr.fedorainfracloud.org/coprs/nonamedotc/nbconvert-6.0.7/builds/