Fix crash in doing tags

tags is an array, not a map in this context.

Author: opax

bin/commands/tags.rb

@@ -60,7 +60,7 @@
     elsif options[:line]
       puts tags.map { |t, _c| t }.to_tags.join(' ')
     else
-      tags.each_key { |t| puts t }
+      tags.each { |t, _| puts t }
     end
   end
 end