voxpupuli-acceptance: Require 4.2 or newer

4.2 allows us to set user and password for curl_command in acceptance
tests. That will allow us to cleanup some tests.

4.1 is already in foreman-installer-modulesync:

theforeman/foreman-installer-modulesync@d0f38a0

Author: bastelfreak

Gemfile

@@ -12,7 +12,7 @@ gem 'voxpupuli-test', '~> 9.0', {"groups"=>["test"]}
 gem 'github_changelog_generator', '>= 1.15.0', {"groups"=>["development"]}
 gem 'puppet_metadata', '~> 4.0'
 gem 'puppet-blacksmith', '>= 6.0.0', {"groups"=>["development"]}
-gem 'voxpupuli-acceptance', '~> 3.4', {"groups"=>["system_tests"]}
+gem 'voxpupuli-acceptance', '~> 4.2', {"groups"=>["system_tests"]}
 gem 'puppetlabs_spec_helper', {"groups"=>["system_tests"]}
 gem 'webmock', '~> 2.0'
 gem 'oauth'