(MODULES-10988) fix require_relative being not relative enough

In some cases running this outside the default puppet agent config this
can cause issues if the libdir does not end in `lib`.

This fix does away with the extraneous level of relativity and thus avoids
the problem. This is the only place in the module where this pattern was
used.

Author: DavidS

lib/puppet/feature/iis_web_server.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 require 'puppet/util/feature'
-require_relative '../../../lib/puppet_x/puppetlabs/iis/iis_version'
+require_relative '../../puppet_x/puppetlabs/iis/iis_version'
 
 Puppet.features.add(:iis_web_server) do
   PuppetX::PuppetLabs::IIS::IISVersion.supported_version_installed?