- Use latest stable for rustfmt and clippy.
- Update Rust in rust-toolchain and coredeps Docker container to 1.54.0
and test against it.
- Test against 1.48.0 to ensure libdeltachat can be compiled with Debian
bullseye "rustc" and "cargo".
Building aarch64 wheels under qemu takes a long time.
rust 1.52.1 includes fix for cargo that may result in
compilation being stuck: https://github.com/rust-lang/cargo/pull/9201