Misc: Enable nix flakes

packages/tools/games/key-mapper/default.nix

@@ -4,10 +4,12 @@
 , gtk3, gobject-introspection, git, gnome
 , wrapGAppsHook
 , makeDesktopItem
+, fetchFromGitHub
 }:
 
 python3Packages.buildPythonApplication rec {
   pname = "key-mapper";
+  # TODO: Update to 1.2.1
   version = "1.0.0";
 
   buildInputs = [ gobject-introspection gtk3 gnome.adwaita-icon-theme ];
@@ -16,9 +18,11 @@ python3Packages.buildPythonApplication rec {
 
   propagatedBuildInputs = with python3.pkgs; [ setuptools pydbus evdev pygobject3 ];
 
-  src = builtins.fetchGit {
-    url = "https://github.com/sezanzeb/key-mapper.git";
-    ref = version;
+  src = fetchFromGitHub {
+    owner = "sezanzeb";
+    repo = "key-mapper";
+    rev = version;
+    sha256 = "07dgp4vays1w4chhd22vlp9bxc49lcgzkvmjqgbr00m3781yjsf7";
   };
 
   doCheck = false;