(maint) update test matrix with latest puppet collections

This commit updates the winrm acceptance tests to validate active agent streams. The newest puppet_agent module no longer supports puppet6 forcing this updated.

Author: donoghuc

spec/integration/apply_spec.rb

@@ -9,8 +9,8 @@
 require 'bolt_spec/run'
 
 TEST_VERSIONS = [
-  [6, 'puppet6'],
-  [7, 'puppet']
+  [7, 'puppet7'],
+  [8, 'puppet8']
 ].freeze
 
 describe 'apply', apply: true do