Update debruijn-graph-assembly tuto: Bandage tool version

If we could update this tutorial https://training.galaxyproject.org/topics/assembly/tutorials/debruijn-graph-assembly/tutorial.html#hands-on-bandage to clarify which version of Bandage to use, I think that would help to avoid some usage errors. The most current of bandage fails with velvetg output but the older version works fine.

Testing history: https://usegalaxy.eu/u/jenj/h/debruijn-graph-edit-with-bandage

Reported at https://help.galaxyproject.org/t/bandage-image-error/13917