add nixpkgs 23.05 to flake inputs

flake.lock

@@ -256,6 +256,21 @@
         "type": "github"
       }
     },
+    "nixpkgs-stable_2": {
+      "locked": {
+        "lastModified": 1699596684,
+        "narHash": "sha256-XSXP8zjBZJBVvpNb2WmY0eW8O2ce+sVyj1T0/iBRIvg=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "da4024d0ead5d7820f6bd15147d3fe2a0c0cec73",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "ref": "nixos-23.05",
+        "type": "indirect"
+      }
+    },
     "pre-commit": {
       "inputs": {
         "flake-compat": "flake-compat",
@@ -321,7 +336,8 @@
         "getchvim": "getchvim",
         "home-manager": "home-manager",
         "lanzaboote": "lanzaboote",
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "nixpkgs-stable": "nixpkgs-stable_2"
       }
     },
     "rust-overlay": {

flake.nix

@@ -3,6 +3,7 @@
 
   inputs = {
     nixpkgs.url = "nixpkgs/nixos-unstable";
+    nixpkgs-stable.url = "nixpkgs/nixos-23.05";
 
     flake-parts = {
       url = "github:hercules-ci/flake-parts";