Relax cloudpickle constraint

[nkpart]

Why

Prefect 3.6.28+ requires cloudpickle>=3.1.1, but block-cascade's existing ^2.0 constraint prevents downstream projects from upgrading Prefect for SCC remediation.

What

• Relax block-cascade's cloudpickle constraint to >=2.0,<4.0
• Bump block-cascade to 3.2.1 for a publishable patch release

Risk Assessment

Low — this is a dependency metadata change only, and focused executor tests pass with the resolved dependency set.

References

• FAB-2603
• Tested: poetry check
• Tested: poetry run pytest tests/test_local_executor.py tests/test_vertex_executor.py -q

---

Update May 8, 09:20: Locked and tested cloudpickle 3.1.2.

• Updated poetry.lock to resolve cloudpickle==3.1.2
• Tested: poetry run pytest tests/test_local_executor.py tests/test_vertex_executor.py tests/test_databricks_executor.py tests/executors/databricks/resource/test_python_library.py -q
• Tested after poetry sync --without torch: poetry run pytest -q (46 passed, 1 skipped)

[AsherWright]

Might be worth testing this to confirm cloudpickle3 works fine

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[nkpart]

Might be worth testing this to confirm cloudpickle3 works fine

@AsherWright yeah good call. I've validated locally that the entire API surface we're using with cloudpickle works in both 2 and 3. I've now updated the lockfile here so it's using 3 in the test suite (which covers some but all uses, covering all would require too many mocks, I dont think we should).