cubicweb-dataio #3367828 missing dependency declarations on librdflib [validation pending]

Both in __pkginfo__.py and debian/control

prioritynormal
typebug
done in0.4.0
load0.100
load left0.000
closed by#f598b038dc50 Add dependency declarations for librdf/rdflib (Closes #3367828)
patchAdd dependency declarations for librdf/rdflib (Closes #3367828) [applied]