Add deprecation notice

[RissyRan]

Description

Add deprecation notice

Tests

Please describe the tests that you ran on TPUs to verify changes.

Instruction and/or command lines to reproduce your tests: ...
N/A

List links for your tests (use go/shortn-gen for any internal link): ...
N/A

Checklist

Before submitting this PR, please make sure (put X in square brackets):

• I have performed a self-review of my code.
• I have necessary comments in my code, particularly in hard-to-understand areas.
• I have run one-shot tests and provided workload links above if applicable.
• I have made or will make corresponding changes to the doc if needed.

[EricLeFort]

Do we plan to maintain this repo still? Perhaps we should mark it as obsolete rather than deprecated?

[will-cromar]

Do we plan to maintain this repo still? Perhaps we should mark it as obsolete rather than deprecated?

Almost all of the tests are migrated. The last few PyTorch/XLA tests will move before the next release in March.

[RissyRan]

Do we plan to maintain this repo still? Perhaps we should mark it as obsolete rather than deprecated?

We won't maintain this repo anymore. I plan to add a notice to say it's going to deprecate. And then sometime in Q1, will mark this repo as readable only. We will decide if we want to obsolete/delete this repo, or keep it as an example for external users.