Merge branch 'security_rack-cors_1.0.6' into 'master'

Security related update in Gemfile for rack-cors

See merge request gitlab-org/gitlab!24152

Gemfile

@@ -84,7 +84,7 @@ gem 'net-ldap'
 # API
 gem 'grape', '~> 1.1.0'
 gem 'grape-entity', '~> 0.7.1'
-gem 'rack-cors', '~> 1.0.0', require: 'rack/cors'
+gem 'rack-cors', '~> 1.0.6', require: 'rack/cors'
 
 # GraphQL API
 gem 'graphql', '~> 1.9.11'