add again multi_json as dependency (#97)

* add again multi_json as dependency

* Update cf-uaa-lib.gemspec

* Update cf-uaa-lib.gemspec

Author: strehle

cf-uaa-lib.gemspec

@@ -31,6 +31,7 @@ Gem::Specification.new do |s|
   s.require_paths = ['lib']
 
   # dependencies
+  s.add_dependency 'multi_json', '>= 1.12.1', '< 1.16'
   s.add_dependency 'json_pure', '~>2.7'
   s.add_dependency 'httpclient', '~> 2.8', '>= 2.8.2.4'
   s.add_dependency 'addressable', '~> 2.8', '>= 2.8.0'