Running parallel tests require brianium/paratest (#8671)

* Running parallel tests require brianium/paratest

* Update testing.md

---------

Co-authored-by: Taylor Otwell <taylor@laravel.com>

testing.md

@@ -107,9 +107,11 @@ php artisan test --testsuite=Feature --stop-on-failure
 <a name="running-tests-in-parallel"></a>
 ### Running Tests In Parallel
 
-By default, Laravel and PHPUnit execute your tests sequentially within a single process. However, you may greatly reduce the amount of time it takes to run your tests by running tests simultaneously across multiple processes. To get started, ensure your application depends on version `^5.3` or greater of the `nunomaduro/collision` package. Then, include the `--parallel` option when executing the `test` Artisan command:
+By default, Laravel and PHPUnit execute your tests sequentially within a single process. However, you may greatly reduce the amount of time it takes to run your tests by running tests simultaneously across multiple processes. To get started, you should install the `brianium/paratest` Composer package as a "dev" dependency. Then, include the `--parallel` option when executing the `test` Artisan command:
 
 ```shell
+composer require brianium/paratest --dev
+
 php artisan test --parallel
 ```