devenv: work-around failing test on aarch64 using latest nixpkgs

The failing test:

    ```
    ---- test::test_nonexistent_script stdout ----
    thread 'test::test_nonexistent_script' panicked at devenv-tasks/src/lib.rs:1106:9:
    assertion failed: `(left matches right)`

    Diff < left / right > :
    <[
    <    (
    <        "myapp:task_1",
    <        Completed(
    <            Failed(
    <                46.911286ms,
    <                TaskFailure {
    <                    stdout: [],
    <                    stderr: [],
    <                    error: "Task exited with status: exit status: 127",
    <                },
    <            ),
    <        ),
    <    ),
    <]
    >[(task_1,
    >TaskStatus::Completed(TaskCompleted::Failed(_, TaskFailure {
    >stdout: _, stderr: _, error })))]
    >if
    >error == "No such file or directory (os error 2)" && task_1 == "myapp:task_1"
    ```

flake.nix

@@ -62,7 +62,11 @@
         {
           inherit unblob;
           default = unblob;
-          inherit (devenv.packages.${system}) devenv;
+          devenv = devenv.packages.${system}.devenv.overrideAttrs (_: {
+            checkFlags = [
+              "--skip=test::test_nonexistent_script"
+            ];
+          });
         });
 
       checks = forAllSystems (system: nixpkgsFor.${system}.unblob.tests // self.devShells.${system});