Heads up: Updating opencascade to 8.x

[Richard Shaw]

Assuming test builds go well in COPR I intend to update opencascade in
Rawhide only at this time unless there's a need for other branches.

Affected packages are:
f3d
gmsh - still failing for unrelated reasons.
kicad
netgen-mesher
prusa-slicer
python-cascadio
vtk

Thanks,
Richard