ci(formatting): Enable check in project root (#426)

resolves #238

Author: shivaraj-bh

dev/nix/pre-commit.nix

@@ -1,9 +1,10 @@
-{ ... }:
+{ inputs, ... }:
 {
   perSystem = { pkgs, lib, ... }: {
     pre-commit = {
       check.enable = true;
       settings = {
+        rootSrc = lib.mkForce inputs.services-flake;
         hooks = {
           nixpkgs-fmt.enable = true;
           commitizen.enable = true;