update excluded_interface_re type to String (#696)

Current version expected an array of strings which broke
the network/conf.yaml file as datadog-agent threw an error.

Author: florusboth

manifests/integrations/network.pp

@@ -14,17 +14,15 @@
 #     'lo0',
 #     'lo',
 #    ],
-#    excluded_interface_re => [
-#    'eth1.*'
-#    ]
+#    excluded_interface_re = 'eth1.*',
 #    combine_connection_states => true
 #  }
 #
 #
 class datadog_agent::integrations::network(
   Boolean $collect_connection_state = false,
   Array[String] $excluded_interfaces = ['lo','lo0'],
-  Array $excluded_interface_re = [],
+  String $excluded_interface_re = '',
   Boolean $combine_connection_states = true,
 ) inherits datadog_agent::params {
   include ::datadog_agent

templates/agent-conf.d/network.yaml.erb

@@ -11,9 +11,6 @@ instances:
 <% end ) -%>
 <% end -%>
 <% if !@excluded_interface_re.empty? -%>
-    excluded_interface_re:
-<%- (@excluded_interface_re.each do |interface| -%>
-      - <%= interface %>
-<% end ) -%>
+    excluded_interface_re: <%= @excluded_interface_re %>
 <% end -%>
     combine_connection_states: <%= @combine_connection_states %>