Bump rackup from 2.2.0 to 2.2.1

Bumps [rackup](https://github.com/rack/rackup) from 2.2.0 to 2.2.1.
- [Release notes](https://github.com/rack/rackup/releases)
- [Changelog](https://github.com/rack/rackup/blob/main/releases.md)
- [Commits](rack/rackup@v2.2.0...v2.2.1)

---
updated-dependencies:
- dependency-name: rackup
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

gems.locked

@@ -37,7 +37,7 @@ GEM
       rack (>= 3.0.0)
     rack-test (2.1.0)
       rack (>= 1.3)
-    rackup (2.2.0)
+    rackup (2.2.1)
       rack (>= 3)
     rainbow (3.1.1)
     rake (13.2.1)