unclutter: add missing licence (publicDomain)

+1
+1
pkgs/tools/misc/unclutter/default.nix
··· 32 ''; 33 maintainers = with maintainers; [ domenkozar ]; 34 platforms = platforms.unix; 35 }; 36 }
··· 32 ''; 33 maintainers = with maintainers; [ domenkozar ]; 34 platforms = platforms.unix; 35 + license = stdenv.lib.licenses.publicDomain; 36 }; 37 }