Create a new exception when the Entrypoint is not defined.

Author: shulard

src/Exception/UndefinedBuildException.php

@@ -0,0 +1,14 @@
+<?php
+
+/*
+ * This file is part of the Symfony WebpackEncoreBundle package.
+ * (c) Fabien Potencier <[email protected]>
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\WebpackEncoreBundle\Exception;
+
+class UndefinedBuildException extends \InvalidArgumentException
+{
+}