build(deps): bump rack from 3.0.8 to 3.0.9.1 in /assets/dora

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>

assets/dora/Gemfile.lock

@@ -6,7 +6,7 @@ GEM
     json (2.7.1)
     mustermann (3.0.0)
       ruby2_keywords (~> 0.0.1)
-    rack (3.0.8)
+    rack (3.0.9.1)
     rack-protection (4.0.0)
       base64 (>= 0.1.0)
       rack (>= 3.0.0, < 4)