flake: delete officialRelease

officialRelease no longer needs to be in here because
lix-project/lix#406 was fixed, so we can
delete it.

flake.lock

@@ -36,11 +36,11 @@
     "lix": {
       "flake": false,
       "locked": {
-        "lastModified": 1718767907,
-        "narHash": "sha256-gpd+mGQxqVHw2kO6rSPQel8TkChHh9UpqxjsmQi0QJM=",
-        "rev": "85f282ef572577899b3d80ba8def1b920a386218",
+        "lastModified": 1722484894,
+        "narHash": "sha256-mmbf3xFov+q8h+44xx3jI/RQnIqhSbVa6ljWYV/jF3c=",
+        "rev": "a3ab2cc78a736109435f3cc8e1364fcc366c6c97",
         "type": "tarball",
-        "url": "https://git.lix.systems/api/v1/repos/lix-project/lix/archive/85f282ef572577899b3d80ba8def1b920a386218.tar.gz"
+        "url": "https://git.lix.systems/api/v1/repos/lix-project/lix/archive/a3ab2cc78a736109435f3cc8e1364fcc366c6c97.tar.gz"
       },
       "original": {
         "type": "tarball",

overlay.nix

@@ -7,9 +7,6 @@ let
   # https://github.com/nixos/nixpkgs/blob/6afb255d976f85f3359e4929abd6f5149c323a02/nixos/modules/config/nix.nix#L121
   lixPackageFromSource = final.callPackage (lix + "/package.nix") ({
     versionSuffix = "-${versionSuffix}";
-    # FIXME: do this more sensibly for future releases
-    # https://git.lix.systems/lix-project/lix/issues/406
-    officialRelease = false;
   });
 
   # These packages depend on Nix features that Lix does not support