chore(nix): update flake.nix to version v2.5.13 [skip ci]

Author: github-actions[bot]

flake.nix

@@ -17,7 +17,7 @@
       perSystem = {pkgs, ...}: {
         packages.default = pkgs.stdenvNoCC.mkDerivation (finalAttrs: {
           pname = "aicommit2";
-          version = "v2.5.12";
+          version = "v2.5.13";
           src = self;
 
           pnpmDeps = pkgs.pnpm.fetchDeps {