fix system.stateVersion for tests

Author: Mic92

tests/build-profile.nix

@@ -16,6 +16,6 @@
       device = "/dev/disk/by-uuid/00000000-0000-0000-0000-000000000000";
       fsType = "btrfs";
     };
-    system.stateVersion = lib.version;
+    system.stateVersion = config.system.nixos.release;
   })
 ]).config.system.build.toplevel