Remove the vendor directory in .gitignore as these dependencies are needed for php-imap

plugins/php-imap/vendor/psr/container/src/NotFoundExceptionInterface.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace Psr\Container;
+
+/**
+ * No entry was found in the container.
+ */
+interface NotFoundExceptionInterface extends ContainerExceptionInterface
+{
+}