Update the rust toolchain to nightly-2024-04-21

[zpzigi754]

This PR updates rust toolchain from nightly-2023-09-05 (rustc 1.74) to nightly-2024-04-21 (rustc 1.79). The update will fix the previous error in AnalysisHub while preserving the functionalities from cargo install.

[Summary of changes]

// The below are all suggested by either `cargo clippy` or `cargo check`.
- Use `addr_of_mut!()` and `addr_of!()` macros
- Use `&[u8]` instead of `&Vec<u8>`
- Use `get(x)` and `get_mut(x)` instead of `iter().nth(x)` and `iter_mut().nth(x)`
- Use `into()` instead of `try_into().or(Err(Error::RmiErrorInput))?`
- Use `u8::MAX` instead of `core::u8::MAX`
- Remove extern keyword in panic handler
- Change .cargo/config to .cargo/config.toml