Bump rack from 2.2.7 to 2.2.9

Bumps [rack](https://github.com/rack/rack) from 2.2.7 to 2.2.9.
- [Release notes](https://github.com/rack/rack/releases)
- [Changelog](https://github.com/rack/rack/blob/main/CHANGELOG.md)
- [Commits](rack/rack@v2.2.7...v2.2.9)

---
updated-dependencies:
- dependency-name: rack
  dependency-type: indirect
...

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

Gemfile.lock

@@ -60,7 +60,7 @@ GEM
       stringio
     public_suffix (5.0.1)
     racc (1.7.3)
-    rack (2.2.7)
+    rack (2.2.9)
     rack-capture (0.4.0)
       rack
     ruby2_keywords (0.0.5)