Bump rack from 3.1.15 to 3.1.16 in /benchmarks

Bumps [rack](https://github.com/rack/rack) from 3.1.15 to 3.1.16.
- [Release notes](https://github.com/rack/rack/releases)
- [Changelog](https://github.com/rack/rack/blob/main/CHANGELOG.md)
- [Commits](rack/rack@v3.1.15...v3.1.16)

---
updated-dependencies:
- dependency-name: rack
  dependency-version: 3.1.16
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

benchmarks/Gemfile.lock

@@ -41,7 +41,7 @@ GEM
       webrick
     puma (6.6.0)
       nio4r (~> 2.0)
-    rack (3.1.15)
+    rack (3.1.16)
     rack-protection (4.1.1)
       base64 (>= 0.1.0)
       logger (>= 1.6.0)