Pin langgraph-checkpoint-postgres to resolve Python 3.11 CI import failure

[Copilot]

The Tests (Python 3.11) GitHub Actions job failed during test collection due to dependency skew in the LangGraph checkpoint stack. An unconstrained install of langgraph-checkpoint-postgres pulled a newer checkpoint package incompatible with the repo’s pinned langgraph==0.1.19.

• Root cause

  • langgraph-checkpoint-postgres was unpinned, allowing resolver drift to a version line that introduces Reviver(allowed_objects=...), which is incompatible with the runtime dependency set in this repository.

• Change

  • Pinned langgraph-checkpoint-postgres to a compatible version in requirements.txt:
    • langgraph-checkpoint-postgres==1.0.9

• Impact

  • Stabilizes dependency resolution for the CI Python 3.11 environment and prevents import-time failure in service/test_service.py collection.

# requirements.txt
-langgraph-checkpoint-postgres
+langgraph-checkpoint-postgres==1.0.9

[Roshanrameshhub]

Langraph checkpoint's version is not mentioned