chore: Update protobuf dependency to latest

Author: bryantbiggs

crates/shim-protos/Cargo.toml

@@ -49,9 +49,7 @@ required-features = ["async"]
 
 [dependencies]
 async-trait = { workspace = true, optional = true }
-# protobuf 3.5 introduces a breaking change: https://github.com/containerd/rust-extensions/issues/295
-# pinning to <3.5.0 until we can update the generated code
-protobuf = ">= 3.0, <3.5.0"
+protobuf = "3.7.2"
 ttrpc = "0.8.3"
 
 [build-dependencies]