use PDK 3.2.0 (Gemfile): update pdk (3.2.0)

Gemfile

@@ -27,7 +27,7 @@ group :development do
   gem "beaker-docker",                                           require: false
   gem "beaker-puppet_install_helper",                            require: false
   gem "beaker-module_install_helper",                            require: false
-  gem "pdk", '<= 2.5.0',                                         require: false
+  gem "pdk", '3.2.0',                                            require: false
 end
 group :system_tests do