Fix syntax error in example [ci skip]

README.md

@@ -33,7 +33,7 @@ Mercenary.program(:jekyll) do |p|
  p.command(:new) do |c|
  c.syntax "new PATH" # do not include the program name or super commands
  c.description "Creates a new Jekyll site scaffold in PATH"
- c.option 'blank', '--blank', 'Initialize the new site without any content."
+ c.option 'blank', '--blank', 'Initialize the new site without any content.'
 
  c.action do |args, options|
  Jekyll::Commands::New.process(args, blank: options['blank'])