Bump rack from 2.2.6.2 to 2.2.6.4 (#292)

Bumps [rack](https://github.com/rack/rack) from 2.2.6.2 to 2.2.6.4.
- [Release notes](https://github.com/rack/rack/releases)
- [Changelog](https://github.com/rack/rack/blob/main/CHANGELOG.md)
- [Commits](rack/rack@v2.2.6.2...v2.2.6.4)

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

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Gemfile.lock

@@ -231,7 +231,7 @@ GEM
     pundit (2.2.0)
       activesupport (>= 3.0.0)
     racc (1.6.0)
-    rack (2.2.6.2)
+    rack (2.2.6.4)
     rack-mini-profiler (3.0.0)
       rack (>= 1.2.0)
     rack-protection (2.1.0)