fix dep version

Signed-off-by: Jay Lee <BusyJayLee@gmail.com>

Author: BusyJay

Cargo.toml

@@ -31,7 +31,7 @@ fail = { version = "0.4", optional = true }
 getset = "0.1.1"
 protobuf = "2"
 thiserror = "1.0"
-raft-proto = { path = "proto", version = "0.6.0-alpha", default-features = false }
+raft-proto = { path = "proto", version = "0.6.0", default-features = false }
 rand = "0.8"
 slog = "2.2"
 slog-envlogger = { version = "2.1.0", optional = true }