Add an option to install PHPUnit (#256)

* Add an option to install PHPUnit

* Fix style

Author: likeadeckofcards

src/NewCommand.php

@@ -37,6 +37,7 @@ protected function configure()
             ->addOption('stack', null, InputOption::VALUE_OPTIONAL, 'The Breeze / Jetstream stack that should be installed')
             ->addOption('teams', null, InputOption::VALUE_NONE, 'Indicates whether Jetstream should be scaffolded with team support')
             ->addOption('pest', null, InputOption::VALUE_NONE, 'Installs the Pest testing framework')
+            ->addOption('phpunit', null, InputOption::VALUE_NONE, 'Installs the PHPUnit testing framework')
             ->addOption('prompt-breeze', null, InputOption::VALUE_NONE, 'Issues a prompt to determine if Breeze should be installed')
             ->addOption('prompt-jetstream', null, InputOption::VALUE_NONE, 'Issues a prompt to determine if Jetstream should be installed')
             ->addOption('force', 'f', InputOption::VALUE_NONE, 'Forces install even if the directory already exists');
@@ -329,6 +330,10 @@ protected function testingFramework(InputInterface $input, OutputInterface $outp
             return 'pest';
         }
 
+        if ($input->getOption('phpunit')) {
+            return 'phpunit';
+        }
+
         $testingFrameworks = [
             'pest',
             'phpunit',