roll mime_types in gemspec back too

Author: mprastzp

zendesk_api.gemspec

@@ -29,6 +29,6 @@ Gem::Specification.new do |s|
  s.add_runtime_dependency "hashie", ">= 1.2", "< 4.0", "!= 3.3.0"
  s.add_runtime_dependency "inflection"
  s.add_runtime_dependency "multipart-post", "~> 2.0"
- s.add_runtime_dependency "mime-types", "~> 2.99"
+ s.add_runtime_dependency "mime-types", "~> 1.25"
  s.add_runtime_dependency "scrub_rb", "~> 1.0.1"
 end