Update checkpubs.rb

Author: rct225

_plugins/checkpubs.rb

@@ -24,7 +24,7 @@ def generate(site)
 
         publication = Record.new(msg, pub_hash)
         publication.key 'focus-area', set: focus_areas if pub_hash.key? 'focus-area'
-        publication.key 'challenge-area', set: focus_areas if pub_hash.key? 'challenge-area'
+        publication.key 'challenge-area', set: challenge_areas if pub_hash.key? 'challenge-area'
         # rubocop:disable Layout/LineLength
         publication.key 'project', :optional, set: projects unless local_fa && local_fa < projectless && local_ca && local_ca < projectless
         # rubocop:enable Layout/LineLength