bundlerUpdateScript: Fix evaluation with allowAliases = false

Reverts https://github.com/NixOS/nixpkgs/commit/38ffd641e0da8f37b82858ebd7cd679fa4716b66

pkgs/development/ruby-modules/bundler-update-script/default.nix

@@ -1,11 +1,11 @@
-{ runtimeShell, lib, writeScript, bundix, bundler, bundler-audit, coreutils, git, nix_2_3 }:
+{ runtimeShell, lib, writeScript, bundix, bundler, bundler-audit, coreutils, git, nix }:
 
 attrPath:
 
 let
   updateScript = writeScript "bundler-update-script" ''
     #!${runtimeShell}
-    PATH=${lib.makeBinPath [ bundler bundler-audit bundix coreutils git nix_2_3 ]}
+    PATH=${lib.makeBinPath [ bundler bundler-audit bundix coreutils git nix ]}
     set -o errexit
     set -o nounset
     set -o pipefail
@@ -13,7 +13,7 @@ let
     attrPath=$1
 
     toplevel=$(git rev-parse --show-toplevel)
-    position=$(nix eval -f "$toplevel" --raw "$attrPath.meta.position")
+    position=$(nix --extra-experimental-features nix-command eval -f "$toplevel" --raw "$attrPath.meta.position")
     gemdir=$(dirname "$position")
 
     cd "$gemdir"