*: Don't leak prost dependency in error types (#3058)

With the current design, a major version bump of `prost` leaks into
all consumers of `prost-codec`.

core/src/lib.rs

@@ -79,6 +79,10 @@ pub use translation::address_translation;
 pub use transport::Transport;
 pub use upgrade::{InboundUpgrade, OutboundUpgrade, ProtocolName, UpgradeError, UpgradeInfo};
 
+#[derive(thiserror::Error, Debug)]
+#[error(transparent)]
+pub struct DecodeError(prost::DecodeError);
+
 use std::{future::Future, pin::Pin};
 
 /// Implemented on objects that can run a `Future` in the background.