nix-plugin-pijul.tests: fix the eval

Without the change the eval fails as:

    $ nix build --no-link -f. nix-plugin-pijul.tests
    error:
       … while calling the 'derivationStrict' builtin
         at <nix/derivation-internal.nix>:34:12:
           33|
           34|   strict = derivationStrict drvAttrs;
             |            ^
           35|

       … while evaluating derivation 'localRepoCheck-nix-2.25.0pre20240920_ca3fc169'
         whose name attribute is located at pkgs/stdenv/generic/make-derivation.nix:336:7

       … while evaluating attribute 'buildCommand' of derivation 'localRepoCheck-nix-2.25.0pre20240920_ca3fc169'
         at pkgs/build-support/trivial-builders/default.nix:59:17:
           58|         enableParallelBuilding = true;
           59|         inherit buildCommand name;
             |                 ^
           60|         passAsFile = [ "buildCommand" ]

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error: function 'anonymous lambda' called with unexpected argument 'nix'
       at pkgs/by-name/ni/nix-plugin-pijul/package.nix:1:1:
            1| {
             | ^
            2|   lib,
       Did you mean lib?

0 files changed, 0 insertions, 0 deletions