Bump rack from 2.1.2 to 2.2.2 (#13108)

Bumps [rack](https://github.com/rack/rack) from 2.1.2 to 2.2.2.
- [Release notes](https://github.com/rack/rack/releases)
- [Changelog](https://github.com/rack/rack/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rack/rack/compare/2.1.2...v2.2.2)

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

Gemfile.lock

@@ -440,7 +440,7 @@ GEM
     pundit (2.1.0)
       activesupport (>= 3.0.0)
     raabro (1.1.6)
-    rack (2.1.2)
+    rack (2.2.2)
     rack-attack (6.2.2)
       rack (>= 1.0, < 3)
     rack-cors (1.1.1)
@@ -747,7 +747,7 @@ DEPENDENCIES
   pry-rails (~> 0.3)
   puma (~> 4.3)
   pundit (~> 2.1)
-  rack (~> 2.1.2)
+  rack (~> 2.2.2)
   rack-attack (~> 6.2)
   rack-cors (~> 1.1)
   rails (~> 5.2.4)