chore(deps): bump sinatra in /buildpacks/buildpack-multi/tests/multi

Bumps [sinatra](https://github.com/sinatra/sinatra) from 4.0.0 to 4.1.1.
- [Changelog](https://github.com/sinatra/sinatra/blob/main/CHANGELOG.md)
- [Commits](sinatra/sinatra@v4.0.0...v4.1.1)

---
updated-dependencies:
- dependency-name: sinatra
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

buildpacks/buildpack-multi/tests/multi/Gemfile.lock

@@ -6,18 +6,18 @@ GEM
     mustermann (3.0.3)
       ruby2_keywords (~> 0.0.1)
     rack (3.1.8)
-    rack-protection (4.1.0)
+    rack-protection (4.1.1)
       base64 (>= 0.1.0)
       logger (>= 1.6.0)
       rack (>= 3.0.0, < 4)
     rack-session (2.0.0)
       rack (>= 3.0.0)
     ruby2_keywords (0.0.5)
-    sinatra (4.1.0)
+    sinatra (4.1.1)
       logger (>= 1.6.0)
       mustermann (~> 3.0)
       rack (>= 3.0.0, < 4)
-      rack-protection (= 4.1.0)
+      rack-protection (= 4.1.1)
       rack-session (>= 2.0.0, < 3)
       tilt (~> 2.0)
     tilt (2.4.0)