Bump rack from 2.2.17 to 2.2.18

Bumps [rack](https://github.com/rack/rack) from 2.2.17 to 2.2.18.
- [Release notes](https://github.com/rack/rack/releases)
- [Changelog](https://github.com/rack/rack/blob/main/CHANGELOG.md)
- [Commits](rack/rack@v2.2.17...v2.2.18)

---
updated-dependencies:
- dependency-name: rack
  dependency-version: 2.2.18
  dependency-type: direct:production
...

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

Author: dependabot[bot]

Gemfile

@@ -4,7 +4,7 @@ group :default do
   if rack_version = ENV['RACK_VERSION']
     gem 'rack', rack_version
   else
-    gem 'rack', '~> 2.2.0'
+    gem 'rack', '~> 2.2.18'
   end
 end
 

Gemfile.lock

@@ -6,7 +6,7 @@ GEM
       rake
       thor (>= 0.14.0)
     diff-lcs (1.6.2)
-    rack (2.2.17)
+    rack (2.2.18)
     rake (13.3.0)
     rspec (3.13.1)
       rspec-core (~> 3.13.0)
@@ -32,6 +32,6 @@ PLATFORMS
 
 DEPENDENCIES
   appraisal
-  rack (~> 2.2.0)
+  rack (~> 2.2.18)
   rake (~> 13.3)
   rspec