Invalid namespaces must be erroring

[dereuromark]

use SprykerShop\CmsBlockWidget\src\SprykerShop\Yves\CmsBlockWidget\Validator\CmsBlockValidator;
use SprykerShop\CmsBlockWidget\src\SprykerShop\Yves\CmsBlockWidget\Validator\CmsBlockValidatorInterface;

Refs https://github.com/spryker/spryker-shop/pull/1281

[dereuromark]

Unfortunately, not every vendor uses a clean naming scheme here

use org\bovigo\vfs\vfsStream;
use org\bovigo\vfs\vfsStreamDirectory;

as such we can probably only blacklist the obvious errors like \src\ in there?
Or we disallow for Spryker* namespaces.
The latter works for use Spryker.*\\[a-z] regex