flake: Replace nixpkgs overrides with cleaner ones

flake.lock

@@ -173,6 +173,22 @@
         "type": "github"
       }
     },
+    "nixpkgs-unstable": {
+      "locked": {
+        "lastModified": 1728018373,
+        "narHash": "sha256-NOiTvBbRLIOe5F6RbHaAh6++BNjsb149fGZd1T4+KBg=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "bc947f541ae55e999ffdb4013441347d83b00feb",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "nixpkgs_2": {
       "locked": {
         "lastModified": 1698318101,
@@ -214,8 +230,8 @@
         "nix-minecraft": "nix-minecraft",
         "nixpkgs": "nixpkgs_3",
         "nixpkgs-2211": "nixpkgs-2211",
-        "sops-nix": "sops-nix",
-        "unstable": "unstable"
+        "nixpkgs-unstable": "nixpkgs-unstable",
+        "sops-nix": "sops-nix"
       }
     },
     "sops-nix": {
@@ -253,22 +269,6 @@
         "repo": "default",
         "type": "github"
       }
-    },
-    "unstable": {
-      "locked": {
-        "lastModified": 1726755586,
-        "narHash": "sha256-PmUr/2GQGvFTIJ6/Tvsins7Q43KTMvMFhvG6oaYK+Wk=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "c04d5652cfa9742b1d519688f65d1bbccea9eb7e",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixos-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
     }
   },
   "root": "root",