rustc-serialize used by eui48 dependency is deprecated

[queria]

rustc-serialize is deprecated, from https://github.com/rust-lang-deprecated/rustc-serialize:
NOTE: This crate is deprecated in favor of [serde](https://serde.rs/).

It results in anything using openstack crate producing:
warning: the following packages contain code that will be rejected by a future version of Rust: rustc-serialize v0.3.24
As also it could have security impact too https://rustsec.org/advisories/RUSTSEC-2022-0004

rustc-serialize comes into rust-openstack as dependency of eui48

├── openstack v0.5.0
│   ├── eui48 v1.1.0
│   │   ├── regex v1.9.0 (*)
│   │   ├── rustc-serialize v0.3.24
│   │   └── serde v1.0.168 (*)

rust-openstack/Cargo.toml

Line 29 in a31ae44

eui48 = { version = "^1.0", features = ["disp_hexstring", "serde"] }

eui48 itself does not seems responsive about this issue for a while already

• Disable the rustc-serialize feature by default abaumhauer/eui48#29
• Remove rustc-serialize from default features. abaumhauer/eui48#34

One possible alternative seems to be to switch from eui48 to macaddr e.g.: ewilken/hap-rs#80

[dtantsur]

Thanks for the heads-up, will take a look once I have some spare time (PRs welcome of course).