More readable fonts for the plots

[NilaBlueshirt]

Hello,

Thanks for providing such a great training source, I like it a lot!

I found the text font that the figures in the "Nextflow Run" tutorial use makes it difficult to read. It would be nice if the font could be changed to a common font or the same font used by the plain text.

Here is the link to the page I'm referring to: https://training.nextflow.io/latest/nextflow_run/02_pipeline/#3-running-modularized-pipelines

Thank you!