Merge pull request #27 from DaveLiddament/fix/build

FIX code style for updated cs-fixer rules

Author: DaveLiddament

src/NamespaceVisibility.php

@@ -8,7 +8,7 @@
 final class NamespaceVisibility
 {
  public function __construct(
- string $namespace = null,
+ ?string $namespace = null,
  bool $excludeSubNamespaces = false,
  ) {
  }