Upgrade to Rust 2021

sdk/program/Cargo.toml

@@ -8,7 +8,7 @@ homepage = "https://solana.com/"
 documentation = "https://docs.rs/solana-program"
 readme = "README.md"
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 bincode = "1.3.1"

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);