[feature]Follow the `default-run` field in 'Cargo.toml' just like `cargo run`

[viruscamp]

Would you please add the feature:
Follow the default-run field in 'Cargo.toml' just like cargo run
See https://doc.rust-lang.org/cargo/reference/manifest.html#the-default-run-field

cargo expand will just work as cargo expand --bin a, with the following configuration:

[package]
default-run = "a"

[[bin]]
name = "a"
path = "a.rs"

[[bin]]
name = "b"
path = "b.rs"