chore(deps): update libz-sys to 1.1.31 for RUSTSEC-2026-0418

libz-sys before 1.1.31 logs the compiler command of its zlib probe, which
with cc 1.6.0 or later includes every environment variable of the build,
and cargo stores that output under target/. It is a build dependency of
shadow-rs via git2 and libgit2-sys; bump it in the lockfile.

Cargo.lock

@@ -3623,9 +3623,9 @@ dependencies = [
 
 [[package]]
 name = "libz-sys"
-version = "1.1.30"
+version = "1.1.31"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f710a23e6dbf193214fd46ca56a9d6864e550abe86202184532ae7275e46de19"
+checksum = "ff20308ecabd635a2dc1dd5834a86c462cca20efba1d5d3ddab1f8aea3455cb2"
 dependencies = [
  "cc",
  "libc",