maintainers: add raskin to the sage team
maintainers: add raskin to the sage team

Meant to do that in b7319d2d35e5f50e777723b3b1c448ad05dc9e9a, but didn't
stage the changes in the actual maintainers list.

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