Update references for python 3 support (follow Rec!1850)
Related MRs LHCb!2214 (merged), Lbcom!395 (merged), Rec!1850 (merged) and Phys!732 (merged)
GitLab jobs artifacts no longer stored forever as of Monday, November 4th 08:30h. Further information under https://cern.ch/otg0152576
Related MRs LHCb!2214 (merged), Lbcom!395 (merged), Rec!1850 (merged) and Phys!732 (merged)