update versions

Gemfile

@@ -3,9 +3,9 @@ source "https://rubygems.org"
 gemspec
 
 group :test do
-  gem "rspec"
-  gem "rubocop"
-  gem "coveralls", require: false
-  gem "simplecov", require: false
-  gem "codeclimate-test-reporter"
+  gem "rspec", "~>3.2"
+  gem "rubocop", "~>0.31"
+  gem "coveralls", "~>0.8", require: false
+  gem "simplecov", "~>0.10", require: false
+  gem "codeclimate-test-reporter", "~>0.4"
 end