Enhancement: Enable blank_line_after_namespace fixer

Author: localheinz

.php-cs-fixer.php

@@ -23,6 +23,7 @@
         'array_indentation' => true,
         'array_syntax' => true,
         'binary_operator_spaces' => true,
+        'blank_line_after_namespace' => true,
         'class_attributes_separation' => true,
         'class_definition' => true,
         'concat_space' => [