Bump rack from 2.2.6.3 to 2.2.6.4

Bumps [rack](https://github.com/rack/rack) from 2.2.6.3 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@v2.2.6.3...v2.2.6.4)

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

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

Author: dependabot[bot]

Gemfile.lock

@@ -231,7 +231,7 @@ GEM
     pundit (2.1.0)
       activesupport (>= 3.0.0)
     racc (1.6.2)
-    rack (2.2.6.3)
+    rack (2.2.6.4)
     rack-attack (6.3.1)
       rack (>= 1.0, < 3)
     rack-contrib (2.3.0)