fix(validate): pin ontology

[cmdoret]

Either we pin the ontology in justfile + manifests, or we keep ussing releases/latest, but need to extend CI to auto embed both nt and ttl. wdyt?

[sabinem]

@cmdoret Looks fine to me.

[rmfranken]

Agreed, I also see you removed -it flag - did that have any effect on succeeding validation, or was it purely the inaccessible ontology link? I will take a look at the CI for publishing both file formats meanwhile, we do it in imaging plaza too so I can hopefully just copy that yaml.

[rmfranken]

OK, on the next release there will be a versioned turtle and nt file, so the converter can pick.

[cmdoret]

Let's pin the ontology in that repo for archival, it will not be pinned in the swisscatplus repository.