hackage2nix.hs: add some older versions to the generated set for 6.12.x support
hackage2nix.hs: add some older versions to the generated set for 6.12.x support

psibi/cabal2nix,bennofs/cabal2nix,spencerjanssen/cabal2nix,Fuuzetsu/cabal2nix,gridaphobe/cabal2nix,jb55/cabal2nix,dmalikov/cabal2nix