chore(deps): update dependency rack to v3

Author: renovate[bot]

examples/subservice-languages/ruby/Gemfile

@@ -4,4 +4,4 @@ source 'https://rubygems.org'
 
 gem 'graphql', '~> 1.10'
 gem 'graphql-schema_directives', '~> 0.0'
-gem 'rack', '~> 2.0'
+gem 'rack', '~> 3.0'

examples/subservice-languages/ruby/Gemfile.lock

@@ -4,7 +4,7 @@ GEM
     graphql (1.11.6)
     graphql-schema_directives (0.0.2)
       graphql (~> 1.9)
-    rack (2.2.9)
+    rack (3.0.10)
 
 PLATFORMS
   x86_64-darwin-19
@@ -13,7 +13,7 @@ PLATFORMS
 DEPENDENCIES
   graphql (~> 1.10)
   graphql-schema_directives (~> 0.0)
-  rack (~> 2.0)
+  rack (~> 3.0)
 
 BUNDLED WITH
    2.2.3