rust-overlay should follow nixpkgs

flake.lock

@@ -31,22 +31,6 @@
         "type": "github"
       }
     },
-    "nixpkgs_2": {
-      "locked": {
-        "lastModified": 1665296151,
-        "narHash": "sha256-uOB0oxqxN9K7XGF1hcnY+PQnlQJ+3bP2vCn/+Ru/bbc=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "14ccaaedd95a488dd7ae142757884d8e125b3363",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixpkgs-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
     "root": {
       "inputs": {
         "nixpkgs": "nixpkgs",
@@ -56,7 +40,9 @@
     "rust-overlay": {
       "inputs": {
         "flake-utils": "flake-utils",
-        "nixpkgs": "nixpkgs_2"
+        "nixpkgs": [
+          "nixpkgs"
+        ]
       },
       "locked": {
         "lastModified": 1677119371,