feat: add version option

src/cli.cr

@@ -23,6 +23,10 @@ module BulkBarrage
         parser.on("report", "Process and report spam email (default: from STDIN)") do
           process_email_spam 
         end
+        parser.on("--version", "Show version") do |flag|
+          STDOUT.puts "#{PROGRAM_NAME} #{VERSION}"
+          exit(0)
+        end
         parser.on("--help", "-h", "show this help") do
           puts parser
         end