update libz-sys version to fix macOS compile error (#10941)

### Problem

Compile error on macOS 10.15.6 with libz-sys crate after pulling to latest `master` commit with Rust 1.47.0 upgrade:

```
The following warnings were emitted during compilation:

warning: src/zlib/gzlib.c:214:15: error: implicitly declaring library function 'snprintf' with type 'int (char *, unsigned long, const char *, ...)' [-Werror,-Wimplicit-function-declaration]
warning:         (void)snprintf(state->path, len + 1, "%s", (const char *)path);
warning:               ^
warning: src/zlib/gzlib.c:214:15: note: include the header <stdio.h> or explicitly provide a declaration for 'snprintf'
warning: 1 error generated.

error: failed to run custom build command for `libz-sys v1.0.25`
```

### Solution

Ran `cargo update -p libz-sys` to upgrade `libz-sys` crate from v1.0.25 to v1.1.2.

Most of the churn in the `Cargo.lock` is probably from a newer version of Cargo which now pins versions by using a `checksum` field in the stanza for each crate.

### Result

Ran `./pants --version` with the upgraded `libz-sys` and native engine rebuilt successfully.

Author: Tom Dyas