Updated gem dependencies.

Gemfile

@@ -3,19 +3,17 @@ source 'https://rubygems.org'
 gemspec
 
 group :development do
-  gem 'rake', '~> 10.4.2'
+  gem 'rake', '~> 12.3.0'
 end
 
 group :testing do
-  gem 'rspec', '~> 3.3.0'
-  gem 'simplecov', '~> 0.10.0', platforms: :mri, require: false
-  gem 'coveralls', '~> 0.8.2', require: false
-  gem 'codeclimate-test-reporter', '~> 0.4.7', group: :test, require: nil
+  gem 'rspec', '~> 3.7.0'
+  gem 'simplecov', '~> 0.14.1', platforms: :mri, require: false
+  gem 'coveralls', '~> 0.8.21', require: false
 end
 
 group :documentation do
   gem 'countloc', '~> 0.4.0', platforms: :mri, require: false
-  gem 'yard', '~> 0.8.7.6', require: false
-  gem 'inch', '~> 0.6.3', platforms: :mri, require: false
-  gem 'redcarpet', '~> 3.3.2', platforms: :mri # understands github markdown
+  gem 'yard', '~> 0.9.12', require: false
+  gem 'redcarpet', '~> 3.4.0', platforms: :mri # understands github markdown
 end