ci(kitchen): rename Kitchen config file

Gemfile

@@ -1,8 +1,5 @@
 source 'https://rubygems.org'
-ruby '2.3.5'
 
-gem 'test-kitchen'
-gem 'kitchen-docker'
-gem 'kitchen-salt'
-gem 'kitchen-inspec'
-gem 'rake'
+gem 'kitchen-docker', '>= 2.9'
+gem 'kitchen-salt',   '>= 0.6.0'
+gem 'kitchen-inspec', '>= 1.1'