pantheon.switchboard: pull upstream fix for meson 0.61
pantheon.switchboard: pull upstream fix for meson 0.61

i18n.merge_file has been ignoring positional arguments for a time and explicitly rejects with error since meson 0.61

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