Merge pull request #523 from zipmark/dependabot/bundler/multi_json-tw-1.15.0

Update multi_json requirement from ~> 1.11.2 to ~> 1.15.0 [ci skip]

Author: bf4

rspec_api_documentation.gemspec

@@ -35,7 +35,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency "minitest", "~> 5.8.4"
   s.add_development_dependency "contracts", "~> 0.17"
   s.add_development_dependency "gherkin", "~> 3.2.0"
-  s.add_development_dependency "multi_json", "~> 1.11.2"
+  s.add_development_dependency "multi_json", "~> 1.15.0"
   s.add_development_dependency "rspec", "~> 3.0"
 
   s.files        = Dir.glob("lib/**/*") + Dir.glob("templates/**/*")