Fix help text: serial must be 9 characters

Author: p3k

lib/main.js

@@ -29,7 +29,7 @@ const mainArgs = [
     type: String,
     description: 'Search string to query for all known authorities and their corresponding IDs'
   },
-  { name: 'serial', alias: 's', type: String, description: 'The full serial number (8 characters)' },
+  { name: 'serial', alias: 's', type: String, description: 'The full serial number (9 characters)' },
   { name: 'update', alias: 'u', type: Boolean, description: 'Update authority data' },
   { name: 'version', alias: 'v', type: Boolean, description: 'Output the version string' }
 ];