Upgrade to Rust 2021

sdk/program/src/message/versions.rs

@@ -89,7 +89,6 @@ impl VersionedMessage {
     /// Compute the blake3 hash of a raw transaction message
     pub fn hash_raw_message(message_bytes: &[u8]) -> Hash {
         use blake3::traits::digest::Digest;
-        use std::convert::TryFrom;
         let mut hasher = blake3::Hasher::new();
         hasher.update(b"solana-tx-message-v1");
         hasher.update(message_bytes);