Update ROOT to 6.26.06 and python 3.10
Add HistFactory model building test that crashes in 6.26.04 due to ShapeFactor bug (https://github.com/root-project/root/pull/10740)
This is a big one ... @zewolffs I'd want you to approve it if it all goes through. I've created a 0.0.x branch that we can use in case we need to keep that branch alive for some/any reason .... Do you think we should deploy that last 0.0.x release before we merge this MR and deploy 0.1.0 with new ROOT?
Edited by Will Buttinger