Resolve "handle several listmasters"

Closes #10 (closed)

manifests/init.pp

@@ -17,7 +17,7 @@
 # @param listdomain
 #   Primary mail domain name. Web interface for Sympa mailing list manager, can
 #   be joined at https://$listdomain
-# @param listmaster Email addresses of listmaster
+# @param listmaster Email addresses of listmasters
 # @param lang Supported language
 # @param topics Defines topics (categories) of the mailing lists.
 #
@@ -37,7 +37,7 @@ class sympa (
   String[1] $aliases_file = 'sympa_aliases',
   String[1] $release = '6.2.74',
   Stdlib::Fqdn $listdomain = 'listes.example.org',
-  Stdlib::Email $listmaster = 'listmaster@example.org',
+  Array[Stdlib::Email] $listmaster = ['listmaster@example.org'],
   Enum['fr'] $lang = 'fr',
   Sympa::Topics $topics = {},
 ) {