CMake: (lib)spnav doesn't show version info in report

[luzpaz]

spnav doesn't show version info in cMake report
:: -- SPNAV: [/usr/lib/libspnav.so] [/usr/include]

ref: https://github.com/FreeCAD/FreeCAD-snap/actions/runs/5862165597/job/15893539114#step:4:549

Related to #61

[luzpaz]

I don't think we're importing libspnav are we?

[furgo16]

It would appear we are shipping it:

ls /snap/freecad/current/usr/lib | grep spnav
libspnav.so.0
libspnav.so.0.1

FreeCAD-snap/snap/snapcraft.yaml

Line 218 in 392dca0

- libspnav0