Build pyroute-0.6.6 for Yoga
    
    Yoga requires pyroute2==0.6.6.
    
    Note that 0.6.9 was only promoted to zed, so i'm reverting to 0.6.6 in yoga branch.
    
    Related-to: https://review.rdoproject.org/r/q/Ib6e2105bb426a75a34a12d9c383886668168f4a4