(CAT-2511) Test docker provisioned SLES 15

Testing SLES 15 through docker. Do not merge.

Author: LukasAud

Gemfile

@@ -64,8 +64,7 @@ group :development, :release_prep do
   gem "puppet-blacksmith", '~> 7.0',      require: false
 end
 group :system_tests do
-  gem "puppet_litmus", '~> 2.0',   require: false, platforms: [:ruby, :x64_mingw] if !ENV['PUPPET_FORGE_TOKEN'].to_s.empty?
-  gem "puppet_litmus", '~> 1.0',   require: false, platforms: [:ruby, :x64_mingw] if ENV['PUPPET_FORGE_TOKEN'].to_s.empty?
+  gem "puppet_litmus", git: 'https://github.com/puppetlabs/puppet_litmus', branch: 'CAT-2476-Address_SLES_failures', require: false, platforms: [:ruby, :x64_mingw]
   gem "CFPropertyList", '< 3.0.7', require: false, platforms: [:mswin, :mingw, :x64_mingw]
   gem "serverspec", '~> 2.41',     require: false
 end