deps: Update Solana v2.3.4 and rust toolchain (#58)

* deps: Update Solana v2.3.4 and rust toolchain

#### Problem

The v2.3 Solana crates are out, and the toolchain on this repo is a bit old.

#### Summary of changes

Bump the Solana version, crates, and rust toolchain.

* Update compute unit numbers

* Commit new compute unit usage

Author: joncinque