(CONT-1001) Add litmus ~> 1.0

Author: Ramesh7

Gemfile

@@ -37,7 +37,7 @@ group :development do
  gem "github_changelog_generator", '= 1.15.2', require: false
 end
 group :system_tests do
- gem "puppet_litmus", '< 1.0.0', require: false, platforms: [:ruby, :x64_mingw]
+ gem "puppet_litmus", '~> 1.0', require: false, platforms: [:ruby, :x64_mingw]
  gem "serverspec", '~> 2.41', require: false
 end