feat: add nixpkgs-mozilla via krops

.versions/nixpkgs-mozilla.json

@@ -0,0 +1,10 @@
+{
+  "url": "https://github.com/mozilla/nixpkgs-mozilla",
+  "rev": "ad227c55c34124cde17b30c9bb28be6cd3c70815",
+  "date": "2021-06-01T15:52:18+02:00",
+  "path": "/nix/store/3ylxhj1n5jzl7c6ifxbgcx48pp2xg9f0-nixpkgs-mozilla",
+  "sha256": "1g33k5da71b11bkia7gjfv70d3bpd0vafidgf9qjrgvld0s2n9r9",
+  "fetchSubmodules": false,
+  "deepClone": false,
+  "leaveDotGit": false
+}

deploy.nix

@@ -24,6 +24,7 @@ let
       stockholm.git = gitFromJson .versions/stockholm.json;
       retiolum.git = gitFromJson .versions/retiolum.json;
       nur.git = gitFromJson .versions/nur.json;
+      nixpkgs-mozilla.git = gitFromJson .versions/nixpkgs-mozilla.json;
       system-secrets.pass = {
         dir = toString ~/.password-store;
         name = "systems/${name}";

overlays/rust.nix

@@ -1,2 +1 @@
-import (builtins.fetchTarball
-  "https://github.com/mozilla/nixpkgs-mozilla/archive/master.tar.gz")
+import <nixpkgs-mozilla>

shell.nix

@@ -40,6 +40,11 @@ let
       url = "https://github.com/nix-community/NUR";
       path = toString .versions/nur.json;
     };
+    nixpkgs-mozilla = {
+      ref = "refs/heads/master";
+      url = "https://github.com/mozilla/nixpkgs-mozilla";
+      path = toString .versions/nixpkgs-mozilla.json;
+    };
   };
 in pkgs.mkShell {
   buildInputs = [