Add missing line break

Before:
```
require:
  - file1.php  - file2.php
```

After:
```
require:
  - file1.php
  - file2.php
```

Author: mbovel

features/bootstrap/FeatureContext.php

@@ -19,7 +19,7 @@
 		if ( ! empty( $composer->autoload->files ) ) {
 			$contents = 'require:' . PHP_EOL;
 			foreach( $composer->autoload->files as $file ) {
-				$contents .= '  - ' . dirname( dirname( dirname( __FILE__ ) ) ) . '/' . $file;
+				$contents .= '  - ' . dirname( dirname( dirname( __FILE__ ) ) ) . '/' . $file . PHP_EOL;
 			}
 			@mkdir( sys_get_temp_dir() . '/wp-cli-package-test/' );
 			$project_config = sys_get_temp_dir() . '/wp-cli-package-test/config.yml';