Bug#980474: freecad: metapackage should depend on the right package versions

[Tobias Frost]

There is now a propsed patch on salsa:
https://salsa.debian.org/science-team/freecad/-/merge_requests/20

Tested as described above, now an apt install freecad will pull all required
packages. The constraints should be binNMU safe and should also allow
something like apt isntall freecad=xyz where e.g xyz is the version of testing
and sid would have e.g xyz+2. 

-- 
tobi