fix --help printing for custom commands

Author: Kelly Selden

bin/commands/default.js

@@ -1,9 +1,12 @@
 'use strict';
 
+const args = require('../../src/args');
 const emberCliUpdate = require('../../src');
 
 module.exports.command = '$0';
 
+module.exports.builder = args;
+
 module.exports.handler = async function handler(argv) {
   let blueprint = argv['blueprint'];
   let from = argv['from'];

bin/ember-cli-update.js

@@ -1,10 +1,7 @@
 #!/usr/bin/env node
 'use strict';
 
-const args = require('../src/args');
-
 require('yargs')
-  .options(args)
   .commandDir('commands')
   .argv;