Bump rack from 3.0.8 to 3.0.9.1

Bumps [rack](https://github.com/rack/rack) from 3.0.8 to 3.0.9.1.
- [Release notes](https://github.com/rack/rack/releases)
- [Changelog](https://github.com/rack/rack/blob/main/CHANGELOG.md)
- [Commits](rack/rack@v3.0.8...v3.0.9.1)

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

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

Gemfile.lock

@@ -155,7 +155,7 @@ GEM
     pg (1.5.4)
     public_suffix (5.0.4)
     racc (1.7.3)
-    rack (3.0.8)
+    rack (3.0.9.1)
     rack-session (2.0.0)
       rack (>= 3.0.0)
     rack-test (2.1.0)