Will panic on newer rust due to `signal_simple`'s use of mem::uninitialized

Hello! In rust-lang/rust#99389 we're making the checks for mem::uninitialized stronger, and this crate runs into those, through the use of signal_simple.

I have reported it upstream, kitsuneninetails/signal-rust#4, but it might be best to instead use a different signal crate.

For reference, the backtrace is

thread 'tests::test_term' panicked at 'attempted to leave type `libc::unix::linux_like::linux::gnu::b64::x86_64::sigaction` uninitialized, which is invalid', /home/jess/.cargo/registry/src/github.com-1ecc6299db9ec823/signal-simple-0.1.1/src/signal.rs:19:29
stack backtrace:
   0: rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::panicking::panic
   3: core::mem::uninitialized
             at /home/jess/src/rust/library/core/src/mem/mod.rs:685:9
   4: signal_simple::signal::signal_internal
             at /home/jess/.cargo/registry/src/github.com-1ecc6299db9ec823/signal-simple-0.1.1/src/signal.rs:19:29
   5: signal_simple::signal::signal
             at /home/jess/.cargo/registry/src/github.com-1ecc6299db9ec823/signal-simple-0.1.1/src/signal.rs:11:5
   6: term_handler::wait_for_term
             at ./src/lib.rs:16:5
   7: term_handler::tests::test_term
             at ./src/lib.rs:33:9
   8: term_handler::tests::test_term::{{closure}}
             at ./src/lib.rs:28:5
   9: core::ops::function::FnOnce::call_once
             at /home/jess/src/rust/library/core/src/ops/function.rs:248:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.


failures:
    tests::test_term