cargo: enable zlib-ng and fast sha1 in gix

I noticed miniz_oxide appears in perf samples. While miniz_oxide is safer, I
think zlib-ng is pretty reliable.

https://docs.rs/gix/latest/gix/#performance

libz-ng-sys is downgraded to 1.1.16 due to the Windows linking issue. The
benchmark result is obtained with libz-ng-sys 1.1.20.

rust-lang/libz-sys#225

```
% hyperfine --sort command --warmup 3 --runs 10 -L bin jj-0,jj-1 \
  'target/release-with-debug/{bin} --ignore-working-copy log README.md'
Benchmark 1: target/release-with-debug/jj-0 ..
  Time (mean ± σ):     256.6 ms ±   4.3 ms    [User: 214.1 ms, System: 38.6 ms]
  Range (min … max):   245.4 ms … 261.2 ms    10 runs

Benchmark 2: target/release-with-debug/jj-1 ..
  Time (mean ± σ):     223.0 ms ±   4.2 ms    [User: 174.7 ms, System: 44.4 ms]
  Range (min … max):   212.4 ms … 225.8 ms    10 runs
```

Cargo.toml

@@ -61,7 +61,7 @@ gix = { version = "0.68.0", default-features = false, features = [
     "attributes",
     "blob-diff",
     "index",
-    "max-performance-safe",
+    "max-performance",
 ] }
 glob = "0.3.1"
 hashbrown = { version = "0.15.2", default-features = false, features = ["inline-more"] }

flake.nix

@@ -98,8 +98,11 @@
             makeWrapper
             pkg-config
 
+            # for libz-ng-sys (zlib-ng)
+            cmake
+
             # for signing tests
-            gnupg 
+            gnupg
             openssh
           ] ++ linuxNativeDeps;
           buildInputs = with pkgs; [