flake: naersk.nixpkgs follows nixpkgs

One less nixpkgs to download.
That way, the dev-shell and the package are actually built from the same
package set.

flake.lock

@@ -2,7 +2,9 @@
   "nodes": {
     "naersk": {
       "inputs": {
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": [
+          "nixpkgs"
+        ]
       },
       "locked": {
         "lastModified": 1698420672,
@@ -20,20 +22,6 @@
       }
     },
     "nixpkgs": {
-      "locked": {
-        "lastModified": 1704161960,
-        "narHash": "sha256-QGua89Pmq+FBAro8NriTuoO/wNaUtugt29/qqA8zeeM=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "63143ac2c9186be6d9da6035fa22620018c85932",
-        "type": "github"
-      },
-      "original": {
-        "id": "nixpkgs",
-        "type": "indirect"
-      }
-    },
-    "nixpkgs_2": {
       "locked": {
         "lastModified": 1704161960,
         "narHash": "sha256-QGua89Pmq+FBAro8NriTuoO/wNaUtugt29/qqA8zeeM=",
@@ -52,7 +40,7 @@
     "root": {
       "inputs": {
         "naersk": "naersk",
-        "nixpkgs": "nixpkgs_2",
+        "nixpkgs": "nixpkgs",
         "utils": "utils"
       }
     },

flake.nix

@@ -1,6 +1,7 @@
 {
   inputs = {
     naersk.url = "github:nix-community/naersk/master";
+    naersk.inputs.nixpkgs.follows = "nixpkgs";
     nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
     utils.url = "github:numtide/flake-utils";
   };