yubioath-desktop: tries to do git clone on mac

[SuperSandro2000]

Describe the bug
yubioath-desktop tries to do pip install and git clone when building on darwin.

To Reproduce
Steps to reproduce the behavior:

1. use darwin machine
2. nix-build -A yubioath-desktop

Expected behavior
A reproducible build.

Screenshots
#104823 (comment)

  WARNING: The directory '/homeless-shelter/Library/Caches/pip' or its parent directory is not owned or is not writable by the current user. The cache has been disabled. Check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
  Collecting git+https://github.com/Yubico/yubikey-manager.git (from -r requirements.txt (line 1))
    Cloning https://github.com/Yubico/yubikey-manager.git to /private/tmp/nix-build-yubioath-desktop-5.0.4.drv-0/pip-req-build-l2b1ssc4
    ERROR: Error [Errno 2] No such file or directory: 'git' while executing command git clone -q https://github.com/Yubico/yubikey-manager.git /private/tmp/nix-build-yubioath-desktop-5.0.4.drv-0/pip-req-build-l2b1ssc4
  ERROR: Cannot find command 'git' - do you have 'git' installed and in your PATH?
  make: *** [Makefile:437: pymodules] Error 1
  make: *** Waiting for unfinished jobs....
cannot build derivation '/nix/store/pz6gryhgnm71gycb03vm2i4gp7nr80nc-env.drv': 2 dependencies couldn't be built
[11 built (2 failed), 134 copied (760.0 MiB), 177.6 MiB DL]
error: build of '/nix/store/pz6gryhgnm71gycb03vm2i4gp7nr80nc-env.drv' failed

Notify maintainers
@Mic92 @risson

Metadata

 - system: `"x86_64-darwin"`
 - host os: `Darwin 19.6.0, macOS 10.15.7`
 - multi-user?: `no`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.3.7`
 - channels(user): `"home-manager, nixpkgs-21.03pre246624.cfed29bfcb2"`
 - nixpkgs: `/Users/user/.cache/nixpkgs-review/pr-104823/nixpkgs`

Maintainer information:

# a list of nixpkgs attributes affected by the problem
attribute:
# a list of nixos modules affected by the problem
module:

[Mic92]

Is a backport required?

[SuperSandro2000]

I don't know if the exact same issue exists on 20.09.