nixos/tests/incus: pass package to releases config (#527223)

nixos/tests/incus/incus-tests-module.nix

@@ -1,10 +1,12 @@
 {
+  config,
   lib,
   pkgs,
   ...
 }:
 let
   jsonFormat = pkgs.formats.json { };
+  cfg = config.tests.incus;
 in
 {
   options.tests.incus = {
@@ -74,7 +76,11 @@ in
             config =
               let
                 releases = import ../../release.nix {
-                  configuration = config.nixosConfig;
+                  configuration = lib.recursiveUpdate config.nixosConfig {
+                    virtualisation.incus = {
+                      inherit (cfg) package;
+                    };
+                  };
                 };
 
                 images = {