python3Packages.ropper: update license to bsd3
python3Packages.ropper: update license to bsd3

Ropper was relicensed to BSD 3-Clause. See:
https://github.com/sashs/Ropper/commit/b8171300096b086495b6d17f9e046b9aee6f829d

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs