mailman: automate year match code

Author: Firefishy

cookbooks/mailman/templates/default/apache.erb

@@ -84,7 +84,8 @@
   ScriptAlias /subscribe /usr/lib/cgi-bin/mailman/subscribe
   ScriptAlias /mailman/ /usr/lib/cgi-bin/mailman/
 
-  <Location ~ "/pipermail/([^/]+)/(2004|2005|2006|2007|2008|2009|2010|2011|2012|2013|2014|2015|2016|2017|2018|2019|2020|2021|2022)">
+  <% last_year = year = Time.now.year - 1  %>
+  <Location ~ "/pipermail/([^/]+)/(<%= (2004..last_year).to_a.join('|') %>)">
     ExpiresActive On
     ExpiresDefault "access plus 180 days"
   </Location>