grpc-protobuf: disable grpc default features

[DarkCat09]

Motivation

grpc-protobuf crate depends on grpc without disabling default features.

I don't want to bring the entire Hickory Resolver into my project since i don't even need DNS resolution, so i add grpc as --no-default-features -F _runtime-tokio.
But then i add grpc-protobuf, and Hickory's dependency tree appears again, because it requires the default features of grpc including dns, which i specifically wanted to opt-out from.

Solution

Set default_features = false for grpc dependency in grpc-protobuf, so this utility crate doesn't opt-in for possibly undesired grpc crate features.

By the way, the same thing is already done in grpc-google (though i don't know if the reason was the same):

grpc-rust/grpc-google/Cargo.toml

Line 17 in 38c7e61

grpc = { path = "../grpc", default-features = false }

[linux-foundation-easycla]

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• ✅ login: DarkCat09 / name: DarkCat09 (5f7e795)

[arjan-bal]

LGTM