bedup: add top-level attribute
bedup: add top-level attribute

Currently I see no standard way of having package name
without the "pythonX.Y-" prefix.

This is replacement to #2339.

SymbiFlow/nixpkgs,NixOS/nixpkgs,triton/triton,NixOS/nixpkgs,triton/triton,NixOS/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,triton/triton,SymbiFlow/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,triton/triton,NixOS/nixpkgs,NixOS/nixpkgs,triton/triton,triton/triton,triton/triton,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,triton/triton,SymbiFlow/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs