flake: use our nixpkgs for all flake inputs

flake.lock

@@ -2,7 +2,9 @@
   "nodes": {
     "devshell": {
       "inputs": {
-        "nixpkgs": "nixpkgs",
+        "nixpkgs": [
+          "nixpkgs"
+        ],
         "systems": "systems"
       },
       "locked": {
@@ -39,7 +41,9 @@
     },
     "naersk": {
       "inputs": {
-        "nixpkgs": "nixpkgs_2"
+        "nixpkgs": [
+          "nixpkgs"
+        ]
       },
       "locked": {
         "lastModified": 1686572087,
@@ -56,35 +60,6 @@
       }
     },
     "nixpkgs": {
-      "locked": {
-        "lastModified": 1677383253,
-        "narHash": "sha256-UfpzWfSxkfXHnb4boXZNaKsAcUrZT9Hw+tao1oZxd08=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "9952d6bc395f5841262b006fbace8dd7e143b634",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixpkgs-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
-    "nixpkgs_2": {
-      "locked": {
-        "lastModified": 1685789966,
-        "narHash": "sha256-pyqctu5Cq1jwymO3Os0/RNj5Nm3q5kmRCT24p7gtG70=",
-        "path": "/nix/store/hnkjxwx9zv2k0gkiznbpkrsvyrzaz6w1-source",
-        "rev": "4eaa9e3eb36386de0c6a268ba5da72cafc959619",
-        "type": "path"
-      },
-      "original": {
-        "id": "nixpkgs",
-        "type": "indirect"
-      }
-    },
-    "nixpkgs_3": {
       "locked": {
         "lastModified": 1685789966,
         "narHash": "sha256-pyqctu5Cq1jwymO3Os0/RNj5Nm3q5kmRCT24p7gtG70=",
@@ -97,27 +72,11 @@
         "type": "indirect"
       }
     },
-    "nixpkgs_4": {
-      "locked": {
-        "lastModified": 1681358109,
-        "narHash": "sha256-eKyxW4OohHQx9Urxi7TQlFBTDWII+F+x2hklDOQPB50=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "96ba1c52e54e74c3197f4d43026b3f3d92e83ff9",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixpkgs-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
     "root": {
       "inputs": {
         "devshell": "devshell",
         "naersk": "naersk",
-        "nixpkgs": "nixpkgs_3",
+        "nixpkgs": "nixpkgs",
         "rust-overlay": "rust-overlay",
         "utils": "utils"
       }
@@ -125,7 +84,9 @@
     "rust-overlay": {
       "inputs": {
         "flake-utils": "flake-utils",
-        "nixpkgs": "nixpkgs_4"
+        "nixpkgs": [
+          "nixpkgs"
+        ]
       },
       "locked": {
         "lastModified": 1686795910,

flake.nix

@@ -3,9 +3,18 @@
 
   inputs = {
     utils.url = "github:numtide/flake-utils";
-    devshell.url = "github:numtide/devshell";
-    naersk.url = "github:nix-community/naersk";
-    rust-overlay.url = "github:oxalica/rust-overlay";
+    devshell = {
+      url = "github:numtide/devshell";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+    naersk = {
+      url = "github:nix-community/naersk";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
   };
 
   outputs = {