error macos download link when build this tools

[lrobot]

nixpkgs-esp-dev/pkgs/esp8266/gcc-xtensa-lx106-elf-bin.nix

Line 14 in 5287d6e

x86_64-darwin = "mac";

wrong download link: https://dl.espressif.com/dl/xtensa-lx106-elf-gcc8_4_0-esp-2020r3-mac.tar.gz
correct download link: https://dl.espressif.com/dl/xtensa-lx106-elf-gcc8_4_0-esp-2020r3-macos.tar.gz

so

x86_64-darwin = "mac"; 

need to be

x86_64-darwin = "macos";