Fix version constraint for protobuf to be compatible with tensorflow-intel 2.18.0 (AIV-801)

[JeremyEastham]

Description

This project contains a strict dependency for protobuf==3.20.2, but this breaks compatibility with tensorflow-intel==2.18.0. This PR relaxes that constraint to protobuf>=3.20.2.

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Checklist

Before submitting a Pull Request, please ensure the following:

• 🚨 This PR does not introduce breaking changes.
• All CI checks (GH Actions) pass.
• Documentation is updated as needed.
• Tests are updated or added as necessary.
• Code is well-commented, especially in complex areas.
• Git history is clean — commits are squashed to the minimum necessary.