fix(dcutr): rename error types to bypass cargo-semver-checks hickup (…

…#3213)

`cargo semver-checks` is still missing features in regards to properly detecting renamed exports. To make our CI pass again, we remove the renamed export, replace it with type-aliases and deprecate them to point users types exported under a module which now follows the conventions set in #2217.

protocols/dcutr/CHANGELOG.md

@@ -2,6 +2,11 @@
 
 - Update to `libp2p-swarm` `v0.42.0`.
 
+- Declare `InboundUpgradeError` and `OutboundUpgradeError` as type aliases instead of renames.
+  This is a workaround for a missing feature in `cargo semver-checks`. See [PR 3213].
+
+[PR 3213]: https://github.com/libp2p/rust-libp2p/pull/3213
+
 # 0.8.0
 
 - Update to `prost-codec` `v0.3.0`.

protocols/dcutr/src/lib.rs

@@ -26,13 +26,11 @@
 pub mod behaviour;
 mod handler;
 mod protocol;
-
-pub use protocol::{
-    inbound::UpgradeError as InboundUpgradeError, outbound::UpgradeError as OutboundUpgradeError,
-    PROTOCOL_NAME,
-};
-
 #[allow(clippy::derive_partial_eq_without_eq)]
 mod message_proto {
     include!(concat!(env!("OUT_DIR"), "/holepunch.pb.rs"));
 }
+
+pub use protocol::PROTOCOL_NAME;
+pub type InboundUpgradeError = protocol::inbound::UpgradeError;
+pub type OutboundUpgradeError = protocol::outbound::UpgradeError;