RUSTSEC-2026-0173 proc-macro-error2 is unmaintained

The author of proc-macro-error2 has confirmed that the crate is no longer maintained and recommends that users migrate away from it. proc-macro-error2 was originally created as a maintained fork of proc-macro-error see RUSTSEC-2024-0370. Both the original crate and this fork are now unmaintained...