We pinned the version of protobuf to protobuf>=3.10,<3.20 because we patch some functionality when converting json <> proto in the AWS Lambda feature server (https://github.com/feast-dev/feast/blob/master/sdk/python/feast/proto_json.py#L18).
protobuf 3.20.0 changes the API we patch - so the version bump needs to happen along with an update to the patched methods.
#2480 has more context.