Bump rack-test from 2.0.2 to 2.1.0

Bumps [rack-test](https://github.com/rack/rack-test) from 2.0.2 to 2.1.0.
- [Release notes](https://github.com/rack/rack-test/releases)
- [Changelog](https://github.com/rack/rack-test/blob/main/History.md)
- [Commits](rack/rack-test@v2.0.2...v2.1.0)

---
updated-dependencies:
- dependency-name: rack-test
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile.lock

@@ -70,7 +70,7 @@ GEM
       pry (>= 0.13, < 0.15)
     public_suffix (5.0.0)
     rack (2.2.4)
-    rack-test (2.0.2)
+    rack-test (2.1.0)
       rack (>= 1.3)
     rainbow (3.1.1)
     rake (13.0.6)