gnu: Add rust-cbindgen-0.23 and rust-cbindgen-0.24.
* nongnu/packages/mozilla.scm (rust-unicode-ident-1, rust-proc-macro2-1.0.43,
rust-syn-1.0.99, rust-textwrap-0.15, rust-windows-x86-64-msvc-0.36,
rust-windows-x86-64-gnu-0.36, rust-windows-i686-msvc-0.36,
rust-windows-i686-gnu-0.36, rust-windows-aarch64-msvc-0.36,
rust-windows-sys-0.36, rust-hashbrown-0.12, rust-object-0.29,
rust-object-0.27, rust-gimli-0.26, rust-addr2line-0.17, rust-backtrace-0.3.66,
rust-parking-lot-core-0.9, rust-once-cell-1.13.0, rust-clap-lex-0.2,
rust-clap-derive-3.2.15, rust-clap-3.2.16, rust-cbindgen-0.24,
rust-cbindgen-0.23): New variables.
Signed-off-by: Jonathan Brielmaier <jonathan.brielmaier@web.de>