Added reference to `parallel` to `doctest` dependencies
Added reference to `parallel` to `doctest` dependencies

timjb/lens,hvr/lens,cdepillabout/lens,omefire/lens,hvr/lens,danidiaz/lens,Fuuzetsu/lens,ddssff/lens,cchalmers/lens,Icelandjack/lens,Gabriel439/lens,rpglover64/lens