Explicitly expose version to avoid release script failure

lazyDerivation limits which attributes are exposed, and version is not currently one of them,
so we need to explicitly expose it.

This fixes this CD failure:

https://github.com/NixOS/nixpkgs-check-by-name/actions/runs/8637321506/job/23679230914

default.nix

@@ -31,15 +31,18 @@ let
     nix-store --init
   '';
 
+  # Determine version from Cargo.toml
+  version = (builtins.fromTOML (builtins.readFile ./Cargo.toml)).package.version;
+
+  # The build with all internal derivation attributes exposed
+  buildUnredacted = pkgs.callPackage ./package.nix {
+    inherit nixpkgsLibPath initNix runtimeExprPath testNixpkgsPath version;
+  };
 
   results = {
     # We're using this value as the root result. By default, derivations expose all of their
     # internal attributes, which is very messy. We prevent this using lib.lazyDerivation
-    build = lib.lazyDerivation {
-      derivation = pkgs.callPackage ./package.nix {
-        inherit nixpkgsLibPath initNix runtimeExprPath testNixpkgsPath;
-      };
-    };
+    build = lib.lazyDerivation { derivation = buildUnredacted; };
 
     shell = pkgs.mkShell {
       env.NIX_CHECK_BY_NAME_EXPR_PATH = toString runtimeExprPath;
@@ -132,4 +135,6 @@ results.build // results // {
   # Built by CI
   ci = pkgs.linkFarm "ci" results;
 
+  # Used by CI to determine whether a new version should be released
+  inherit version;
 }

package.nix

@@ -10,10 +10,10 @@
   initNix,
   runtimeExprPath,
   testNixpkgsPath,
+  version,
 }:
 let
   fs = lib.fileset;
-  version = (builtins.fromTOML (builtins.readFile ./Cargo.toml)).package.version;
 in
 rustPlatform.buildRustPackage {
   pname = "nixpkgs-check-by-name";

scripts/release.sh

@@ -16,7 +16,7 @@ root=$(git rev-parse --show-toplevel)
 repository=${GITHUB_REPOSITORY:-NixOS/nixpkgs-check-by-name}
 
 # Get the version from the Cargo.toml file
-version=$(nixeval "$root" -A build.version)
+version=$(nixeval "$root" -A version)
 echo "Current version is $version"
 
 if existingRelease=$(gh api \