proc-macro-error is unmaintained

[FreeMasen]

RUSTSEC advisory for this dependency has been was reported in 2024

https://rustsec.org/advisories/RUSTSEC-2024-0370

A warning appears when using cargo audit with a dependency tree of

Dependency tree:
proc-macro-error 0.4.12
└── genawaiter-proc-macro 0.99.1
    └── genawaiter 0.99.1
        └── xot 0.31.2
            └── xee-xpath-type 0.1.4
                └── xee-xpath-ast 0.1.4
                    └── xee-xpath-macros 0.1.4
                        └── xee-interpreter 0.2.0
                            └── xee-xpath-compiler 0.1.5
                               └── xee-xpath 0.1.5