Merge pull request #83 from PennyLaneAI/archive_repo

Redirect people to Lightning monorepo in README.

README.rst

@@ -3,6 +3,15 @@ PennyLane-Lightning-Kokkos Plugin
 
 .. header-start-inclusion-marker-do-not-remove
 
+❗ Warning
+==========
+
+The PennyLaneAI organization has archived this repository, which is a snapshot of PennyLane-Lightning-Kokkos v0.32.
+This backend was integrated into `PennyLane-Lightning <https://github.com/PennyLaneAI/pennylane-lightning>`_ where its development continues.
+We direct users and developers to `PennyLane-Lightning <https://github.com/PennyLaneAI/pennylane-lightning>`_ to report `issues <https://github.com/PennyLaneAI/pennylane-lightning/issues>`_, make `pull requests <https://github.com/PennyLaneAI/pennylane-lightning/pulls>`_, etc.
+
+About
+=====
 The `PennyLane-Lightning-Kokkos <https://github.com/PennyLaneAI/pennylane-lightning-kokkos>`_ plugin provides a fast state-vector simulator written in C++.
 It enables parallel execution with various parallel backends, including C++ threads, OpenMP, CUDA, ROCM/HIP and SYCL via the `Kokkos library <https://github.com/kokkos/kokkos>`_.
 For more details, have a look at our `blog post <https://pennylane.ai/blog/2023/04/pennylane-goes-kokkos-a-novel-hardware-agnostic-parallel-backend-for-quantum-simulations>`_.